Some AMAZING facts on Pleco

Pleco, Plecostomus, common algae sucker, is the algae eater fish commonly found in fish tanks at home. They are silent workers. They never disturb any other fish and they are good. Several things we did not know about this amazing fish which we think you need to know. Pleco can survive without water longer than any other fish can. BUT Ttis does not mean that you try this out by taking the pleco out of your aquarium. Hypostomus Plecostomus are able to breathe atmospheric oxygen. If the air pump on your tank ever fails, your pleco will survive for some time because they are able to shoot to the surface and take a gulp of air.

FACT#1 : Plecos surviving without water for 4 HOURS!

The owner of the video below actually describes that his beloved pleco has survived without water for 4 hours! Check out the video!

Fact#2: They love sucking!

Put your hand into the aquarium and they will eventually just suck on your hand just like their kissing you!

Fact#3: They are tough fellas.

Yes! Even Piranhas are scared of them! Remember to not make your pleco angry!

Fact#4: They eat cucumber.

Look at the pleco in the video below! So cute! 

Suckermouth of Plecostomus Could Inspired Better Suction Devices (Bio-inspiration Example 2)

We observed that the Plecostomus was able to perform suction even under wet environment as we seen them in the aquarium. Or they can even suck on a rock full of slimy algae. This gives us an inspiration on how such action could benefit the human race. Having said that, researcher at University of Washinton's Friday Harbour Laboratories studied on the Northern clingfish and observed that this clingfish was able to produce high suction forces that can support up to 150 times their own body weight even under wet and slimy surfaces. This is something that even the current suction device cannot do. This sparked the idea that if the biomechanics of the clingfish or even the Plecostomus could be mimicked, it would be beneficial for the application of medical devices for surgical operations. Unlike the Plecostomus, the bellies of the clingfish provided the suction instead of their mouth, but either way both of the feature still allowed to be attached to a wet and slimy surface. The belly of the clingfish is like a rim of disc covered with a microscopic hair-like structure which created a layered effect that allowed them to attached to surfaces. On top of that, their disc-shaped bellies are also elastic where they can attach to uneven surfaces. 

The bio-inspiration from this creature is to be able to stick surgical devices into the patient's organs or tissue without harming them. The ability to retract delicate tissue without clamping them is what doctors desired in the laparoscopic surgery.....and the suction disc of the clingfish could lead a new way to manipulate organs without any risk of puncture. Besides for medical field, researchers also wants to develop a new type of tagging tool based on this suction feature to tag onto the body of animals such as whales without puncturing their skin with darts. Other than that, this type of development can also be very useful for shower caddy that uses suction cups as the bathroom is mostly wet all the time.

Figure 1 showed the underside of the clingfish. As seen in the figure, the disc-shaped belly of the clingfish looks very much similar to the suckermouth of the Plecostomus (see the comparison in Figure 2), which is why we believe they could also inspire for better suction devices besides the clingfish. We would also like to share a mind-blowing video on the suction power of the clingfish, you have to see it to believe it.

Figure 1. Underside of the clingfish - the disc-shaped belly

Figure 2. Comparison of the belly of clingfish and suckermouth of Plecostomus

Additional information that might interest you too :)

In addition to that, the Plecotomus was also able to perform suction attachment and respiration simultaneously. The idea of performing suction and respiration at the same time seems contradictory to scientist because the combination of both actions would result in leakage of air from the mouth. Fascinated by such observation, researcher Tom Geerinkx and his team research onto how is was possible for the Plecostomus to perform such paradoxal activity. The research data from Tom and his team found that the muscle oral valve actively separates the post-valvular buccal cavity from the pre-valvular sucker cavity. As such, the change in volume of the pre-valvular cavity are opposed to those of the post-valvular cavity, and this assures the suction function even during exhalation.


Reference

http://www.washington.edu/news/2015/05/04/puget-sounds-clingfish-could-inspire-better-medical-devices-whale-tags/

https://www.researchgate.net/publication/50269275_Suckermouth_armored_catfish_resolve_the_paradox_of_simultaneous_respiration_and_suction_attachment_A_kinematic_study_of_Pterygoplichtys_disjunctivus

Teeth of Plecostomus

     One of the species of the Plecostomus family, Plecostomus cordovae was examined by Theodore H., focusing on the needle-like teeth of pleco fish. The teeth of Plecostomus cordovae are uniform tubes of dentine which contains no enamel, flattened at the tip. The entire set of teeth in each dentary and premaxilla lies in a deep trough in the bone while each tooth attaches by a movable joint just under the overhanging rim of the trough when the tooth is developed completely, as shown in Figure 1.

i., integument of mouth; p.m., premaxilla; t., tooth.

Figure 1: (Left) Ventral aspect of head of Plecostomus cordovae; (Right) Cross-section of premaxilla of Plecostomus cordovae showing development of series of teeth.

     The teeth are piled in vertical series within the jaw, in which the teeth at the bottom being buds in the first stage of development, and those toward the exterior growing progressively more complete and more angular until the last and oldest in the series emerges ready for use. The teeth that break off are replaced by the one below. The dentine is covered by two layers of columnar cells, one outside and another inside the tooth as shown in figure 2. The columnar layer within continues down to the bottom of each papilla and up the adjacent surface of the overlying cap during the earlier stages of the tooth papilla. These layers appear to be identical in the papilla and in the surrounding cap, which suggests that both layers contribute to the deposit of the tooth. It is worth to note that the increase in thickness at the tip is due to the lengthening of individual cells instead of the multiplication of layers.

           

     For more fully developed teeth, the cells within the dentine column become nearly cut off from those outside, as the need to carry materials to the tooth must exist as well as the observed groups of erythrocytes. A capillary passes close to the base of each tooth while sending a loop up into it. Distally the dentine within the tip is transparent, thin and filled with minute canals crossing it as many different angles.

     A series of zones exists along the face of the cavity in which the teeth arise, from bottom to the top. Narrow and nearly straight tip of the teeth formed in the bottom zone; the first segment of the shaft formed in the second zone, preceded by an angle; another segment marked by an opposite bend in the third zone and the final rounded base for articulation with the bone when the tooth is in position for use in the fourth zone. Hence, the growing teeth push those above gradually outward from the bottom of the trough; different effects occur as they come to different levels. Although their nature and factor are unknown, the effects are probably due to a sequence of changes in the secreting tissues. The complete tooth is a lifeless shell as the tissues become less compact within the teeth, eventually shrink away, leaving large gaps and scattered group of cells.

c., columnar cells; cap., capillary; d., dentine; e., erythrocytes

Figure 2: Microscopic section of earliest stages in tooth development of Plecostomus cordovae

Our NEXT POST discussed on how the SUCTION of the Plecostomus' mouth INSPIRED better MEDICAL DEVICES!!!

Reference

http://www.jstor.org/stable/1436721?seq=1#page_scan_tab_contents

Current Bio-inspiration from Fish Skin - Body Armour (Bio-inspiration Example 1)

In the previous post talked about the tough skin of the Pleco that served as a protection from predatory attack. Today’s post we talked about how the fish skin have inspired humanity.

Scientists at MIT and Technion-Israel Institute of Technology have been developing body armour for that was inspired by the fish skin. The newly developed body armour based on the fish skin could lead to new flexible materials for a uniform that can withstand bullets and knives piercing.

Unfortunately, this invention was not inspired by the strong dermal plates of the Pleco, but was inspired by another freshwater fish called the Arapaima Gigas that also exhibit a tough armour skin besides the Pleco. The researchers has observed that the skin of the Arapaima Gigas is so tough that it could protect them from piranha bite. Although though, scientist found that the scales of the Arapaima Gigas is also flexible as they spread the stress created by the piranha’s teeth by flexing and twisting.

Thus, this observation from the Arapaima Gigas gives scientist the idea to develop a tough but flexible body armour for the military as well as security forces to replace the current armour that is heavy.  Scientist, Professor Stephan Rudykh found out that the skin of the Arapaima Gigas consists of the tough outer layer that provides protection and the inner soft elastic layer kept the skin flexible. This is similar to that of the Pleco as discussed in the previous post.

In this development, the flexibility and strength are always the competing against each other. While the strength increases, it always leads to lower flexibility. But Professor Stephan found that they could increase the strength of the armour by 40 times while only reducing the flexibility by 5 times. This was achieved by positioning the artificial hard plastic scale at a certain angle. Right now, the challenge is to develop the right material. But nevertheless, this development is still feasible.

3D printed fish scale - inspiration fro new body armour

Artificial Human Skin-Tissue Engineering

Tissue engineering is another similar field of interest in organism’s skin biomimicry. The study organism skins originate from the field biomaterial. Among the all studies carried out, the most significant and impactful application would be tissue engineering. Countless research and time were dedicated to study the biology of human skins. A unique ability of the human and animal cells which was self-regeneration sparks the interest of mankind to study this unique feature. Throughout the history of tissue engineering, experiments have been conducted to growing cells outside a living organism (in vitro). The aim of tissue engineering was to resort, maintain or even improve the tissue functions that are defective and lost or destroyed due to diseases and accidents. After numerous research cell biology, biomaterial science, imaging and characterization of surface and cell interaction, artificial human skin was developed. This artificial skin, better known as scaffolds are three dimensional porous solid biomaterials designed to perform some of the functions of the human skin. These functions are such as cell-biomaterial interaction, cell adhesion, transport of gases, nutrients and regulatory functions to allow cell survival. The most significant function of the scaffolds are to provoke minimal degree of inflammation and toxicity to the host body. The future approach in tissue engineering is to develop artificial skins with self-healing properties as well as easier adaptation on patients.

Reference

http://www.dailymail.co.uk/sciencetech/article-3029185/The-body-armour-inspired-FISH-scales-Material-lead-bulletproof-uniforms.html

Dhandayuthapani, B. et al., 2011. Polymeric Scaffolds in Tissue Engineering Application: A Review. International Journal of Polymer Science, 2011, pp.1–19. Available at: http://www.hindawi.com/journals/ijps/2011/290602/ 

National Institute of Biomedical Imaging and Bioengineering, 2016, Tissue Engineering and Regenerative Medicine Available at: https://www.nibib.nih.gov/science-education/science-topics/tissue-engineering-and-regenerative-medicine.

Dermal Plates of the Armored Catfish - Pterygoplichthys Pardalis

The Pleco fish, also commonly called the suckermouth fish, was also called by another name which is the armored catfish. The term “armoured” was given primary because the Place fish has a rather tough skin surface at the top of the fish. Because of that, Ebenstein (2015) have carried out a research on the dermal plates of this so called armored catfish. In her research paper, Ebenstein analysed the dermal plates of the Amazonian fish Pterygoplichthys pardalis (Pleco fish) which then characterized it into the structural, chemical and nanomechanical properties. Among the analysis performed by Ebenstein, the most significant discovery was from the scanning electron microscope (SEM) that reviewed that the dermal plates have a sandwich-like structure, it is made up of an inner porous matrix surrounded two external dense layer (Ebenstein et al., 2015).

            For most fishes, their outer skin layer are covered by scales. These scales found on their body are much like the other college-based natural structure such as bones, teeth and mineralized materials (Torres et al., 2008). On the contrary, the armored catfish does not have scales compared to the majority of the fishes, but instead have a rather distinct type of dermal elements such as odontodes, teeth, dermal denticles (like sharkskin) or dermal plates as Ebenstein described it in her research paper. However, a little was known about the structural, chemical and mechanical properties of this dermal plate until Ebenstein’s research in 2015.

            Based on the results obtained in the research of Ebenstein, she discussed that the dermal plates from the Pterygoplichthys pardalis are not flat like those of elasmoid fish scales, but have a 3-dimentional “V” shape as shown in Figure 1. It was measured that the dermal plates are around 15 mm in length and 1.5 mm in thickness (Ebenstein et al., 2015). The internal surface of the plates that are not exposed to water is actually smooth, whereas the external surface has a rough surface due to the presence of tubercles (see Figure 1). The tubercles are referred to as dermal denticles that are tooth-like element. On the other hand, the sharkskin is also referred to as dermal denticles but microscopic observation showed that the structure is not the same as those of the armored catfish.

Figure 1. Dermal plate of armored catfish Pterygoplichthys pardalis 

It was also reported that the tubercles on the dermal plates provided the armored catfish against penetration resistance as well as hydrodynamics (Ebenstein et al., 2015). With that said, the penetrating tooth of the catfish’s predator such as aquatic snakes, freshwater turtles or other predatory fish would have to indent the tubercles first before penetrating the external layer of the dermal plate. When the predator tooth penetrate on its dermal plate, the outer dense layer act as a shield to resist penetration while the inner matrix will deform to absorb the shock from the forces of the predator teeth during the attack, thus this help to increase the toughness of the dermal plate to prevent the fracture and penetration of the soft inner tissue beneath the dermal plates (Ebenstein et al., 2015).

Apart from that, it was also analysed that the tubercles also modify the viscous drag forces of the flowing water, surface shear stress and skin friction of the Pterygoplichthys pardalis (Ebenstein et al., 2015). So even though the dermal denticles of the armored catfish is different from that of the sharkskin, it was debated that both their dermal denticle served the same purpose of reducing drag as they swim.

Apart from structural analysis using SEM, Ebenstein also studied on the chemical properties on the dermal plates of Pterygoplichthys pardalis using FTIR, DSC and XRD that reviewed on the composition of the dermal plates, these results can be referred in the research paper as they are not the main discussion of this literature topic.

Thus, to conclude this literature review, the Pterygoplichthys pardalis does not have scales but rather a dermal plates that has a 3-dimasional “V” shape structure. The main findings from Ebenstein reviews that the tubercles on the external surface of the dermal plate served to provide protection for the Pterygoplichthys pardalis against predator in its habitat and also reviewed that it also modify the water flow across the surface of the fish which provided hydrodynamics.

Be sure to CHECK OUT our NEXT POST where we share how the skin of the fish INSPIRED the development of a NEW TYPE of BODY ARMOUR!!!

Reference

1. Ebenstein, D., Calderon, C., Troncoso, O.P. and Torres, F.G., 2015. Characterization of dermal plates from armored catfish Pterygoplichthys pardalis reveals sandwich-like nanocomposite structure. Journal of the Mechanical Behavior of Biomedical Materials, 45(February), pp.175–182.
2. Torres, F.G. et al., 2008. Characterization of the nanocomposite laminate structure occurring in fish scales from Arapaima Gigas. Materials Science and Engineering C, 28(8), pp.1276–1283.

Habitat and Diet of the Hypostomus Plecostomus

Living environment

The natural habitat of the Pleco fish consisted of streams, rivers and also ponds. The Pleco fish however do preferred slow moving waters which have shelters during the day as they are nocturnal. They tend to seek shelters such as driftwoods and aquatic plants. Thus, one should provide the aquarium with suitable shelter or a ‘hiding place’ if they plan to adopt a Pleco fish. With some inside of the living environment of the Pleco fish, the group have provided the shelters in the form of the short PVC pipes. It was observed that the Pleco adopt themselves well in the PVC pipes and can be found residing inside the pipe most of the time. Providing a hiding place also reduces the stress as well as the aggression of the Pleco fish. Figure 1 and Figure 2 show the PVC pipe as shelter.

Figure 1. PVC pipe as shelter

Figure 2. Pleco fish inside PVC pipe

Diet

Pleco fish exhibit a diverse diet as there are omnivores. Their range of diet include algae, other plant material, insects and even small crustaceans which they can find in the wild.  Fellow Pleco fish owners are advised to provide a similar range of diet in their aquariums. The best choice of food for the Pleco fish are ones which can sink to the bottom, therefore, the group have purchased sinking fish pellets for them.  Figure 3 below shows the fish pellet fed to the Plecos.

Figure 3. Sinking pellets

Although this fish pellets are rich in proteins, but are fairly low in fibre content. To provide a substantial amount of fibre in their diet, fruits and vegetables can be regularly fed to them, but bear in mind not to fed them acidic fruits or vegetables. Many of the website and blogs visited have reviewed that zucchinis are one of the favourite foods of the Pleco fish. We have try feeding the Plecos with zucchinis and they absolutely love it. Besides getting the source of fibre through fruits and vegetables, a common recommendation from websites and blog are to provide the Plecos with driftwoods.

Reference

1. Oscar Fish.com, 2016, Pleco Dietary Needs... Supplementary Food [Online]. Available at: http://www.oscarfish.com/article-home/fish/99-pleco-dietary-needs.html [Accessed: 30 May 2016].
2. Seymor, M., 2014, Common Pleco - The Care, Feeding and Breeding of Common Plecos - Aquarium Tidings [Online]. Available at: http://aquariumtidings.com/common-pleco/ [Accessed: 30 May 2016].

Position of Pleco Mouth

     If you observed closely, different species of fish will have different mouth position. The mouth position of fish, whether it is angled up, ahead or down actually correlates with the trophic ecology of the fishes. The majority of fishes have terminal mouth regardless of trophic habits, which means that their mouth opens forward.  Any deviation from the terminal location of the fish's mouth will usually indicate that their different feeding habitat.

     Compared to other fishes, the Pleco's mouth is positioned on the bottom , which means their mouth open downwards when feeding. This type of fish mouth characterizes the fish as algae eaters or bottom feeders. Fishes with such mouth are termed inferior or subterminal, where most of them belonged to the catfish species.

     One amazing fact about inferior mouth fish is that they too can feed on food that is floating on the water surfaces. Believe it or not, they can position themselves in an upside-down position if the food does not sink to the bottom.

     The video below showed a rare video of our Pleco feeding upside-down on the cucumber we feed them every day. YOU REALLY HAVE TO SEE TO BELIEVE IT!! NO JOKE!!!

Reference

1. Helfman, G., Collette, B., Facey, D and Bowen, B., 2009,  The Diversity of Fishes: Biology, Evolution, and Ecology, 2edn, Wiley.