breeding caves

[kieranvowles]

May be opening a bit of a debate, but, is there any reason not to use plastic products for breeding caves? I have a black square pipe that's the perfect size for my bristlenose to use as a cave, I have a 1.5m lenght that I can cut to the desired length, and as my terracotta cave has broken and I thought I'd try the pipe. Any thoughts?

[Suckermouth]

In a recent study, it's been shown that Hypancistrus zebra prefer rock and clay over plastic PVC. However, it's not noted what color the PVC is, and I suspect that color of the structure has some effect.

[antec]

It's funny that you mention it. recently I have been observing my juvi L018 GNP's for the past two months in their tank with respects to their behaviour, feeding habits, and their relationships with each other. I have placed a few PVC pipes within their tank. http://www.youtube.com/watch?v=pzakRSf5F0A here's a video of the caves @ 0:46. I have noted that they don't really like huddling in their caves as much as their parents. their parents have rocks that I've drilled out as caves and they utilize them to their fullest. the plastic caves, not so much. the PVC is grey in colour with substrate glued with aquarium adhesive all around the outside.

[antec]

In a recent study, it's been shown that Hypancistrus zebra prefer rock and clay over plastic PVC. However, it's not noted what color the PVC is, and I suspect that color of the structure has some effect.

colour may not be an issue. zebras live in deep waters so unless the caves are red in colour I doubt it would make a difference. usually fauna that live in dark places don't develop rods and cones to detect colour in the visible light spectrum. That's why people should never use infrared cameras to record their fish during the night. I believe its the foreign material that causes them to reject their caves... maybe?

[chris521957]

I have just been debating whether to change my caves. ATM i have 3 small ceramic plant pots, cut in half to make 6 caves. The entrances are approx 100mm x 50mm high. I also have 6x50mm Plastic pipes, which i have covered with substrate. I find the plecs dont seem to like the pipes as much as the pots, but the pots are not being used much either. I think the size of the entrance may be putting them off. I am now thinking smaller ceramic caves could be more to their liking and i willl be changing over to the commercially produced caves in the near future. BTW, i added hte substrate to my pipes with superglue, with no detriment to the fish.

[kieranvowles]

Well, I thought I'd try the pipe today, and to my suprise my male found it very quickly and spent a good 10mins trying it out, he's been in and out of it in all positions imaginal, and has now settled grasping the roof of the pipe with his little bristles poking out. I thought about the difference between natural an plastic and the immediate difference was the texture, so I used sand paper to roughen the inside ssurfaces, maybe this is bettle for the eggs to adhere to? Also the pipe I'm using is about 1.5inces square with and about 6inces long with the end blocked off. I will post a pic soon. I will also let you know how it goes for anyone else who may consider plastic.

[stuby]

In a recent study, it's been shown that Hypancistrus zebra prefer rock and clay over plastic PVC. However, it's not noted what color the PVC is, and I suspect that color of the structure has some effect.

I did my own study over the years of breeding plecs.... I didn't try plastic tho. This is basically what I found out and what I have tried. None of my plecs have bred in a slate cave when there is a granite or oak cave available. I've tried rough slate and smooth. Some plecs like the granite over oak and some like oak over granite caves.... depends on the type of pleco. I have tried black, black/white, and brown/white granite caves and have had them breed in all colors but seems they like lighter colors more than darker (black). Some that like oak over granite caves but will breed in the granite caves too if oak isn't available are L174, L180, L129, Peckoltia zwerg, and L411's.

Hope that helps
Chuck

[kieranvowles]

My males bn seems to like his new plastic cave, he's hardly come out since I put it in just over 2 days ago and has even invited the gravid female in to inspect it. Fingers cross l'll have another batch of babie bn's soon.

[Suckermouth]

In a recent study, it's been shown that Hypancistrus zebra prefer rock and clay over plastic PVC. However, it's not noted what color the PVC is, and I suspect that color of the structure has some effect.

colour may not be an issue. zebras live in deep waters so unless the caves are red in colour I doubt it would make a difference. usually fauna that live in dark places don't develop rods and cones to detect colour in the visible light spectrum. That's why people should never use infrared cameras to record their fish during the night. I believe its the foreign material that causes them to reject their caves... maybe?

So what I meant was tint, not hue. While cones require a lot of light for activation, rods can be activated by far fewer photons, and remain useful for many dim-light fish. Loricariids would easily differentiate white and black PVC pipes, but the authors don't mention if they standardized the internal coloration of their caves. I simply raised that point to note that they don't specify if they controlled for tint, a potentially confounding factor. While zebras do live in fairly deep water, to suggest that they don't see visible light makes little sense when they respond to visible light and most fishes that have eyes that we can maintain in the aquarium see in visible light wavelengths. Of course, visual pigments in loricariids have not yet been tested for their spectral sensitivity.

Furthermore, I don't see how recording a fish that can see in infrared with an infrared camera is different from recording a fish that can see visible light with a normal camera. This is assuming fish can even see in the infrared. Although some animals have been shown to be able to detect infrared (most famously are snakes, but one fish has been shown to do so), as far as I know, visual pigments like cones and rods have not been shown to have adapted to detect infrared. Deep-sea fishes are adapted to low light conditions, but have not been shown to detect infrared. Most fish can't even see red light, and it is common practice to use red lights to observe fish during the night. This is supposedly part of why many deep-sea fish are red; they are invisible! Furthermore, red light is quickly attenuated in water anyway, quickly becoming undetectable except at close distances.

I believe its the foreign material that causes them to reject their caves... maybe?

I agree that this is the most likely cause, and it is the point of the experiment I cited.

[Suckermouth]

I have tried black, black/white, and brown/white granite caves and have had them breed in all colors but seems they like lighter colors more than darker (black).

Interesting, that's not what I would've expected...

[stuby]

One exception to that is L104..... they seem to like the black granite to breed in. They ate the oak cave I had for them before they started breeding and I'll have to make another one to see what happens yet.

[antec]

So what I meant was tint, not hue. While cones require a lot of light for activation, rods can be activated by far fewer photons, and remain useful for many dim-light fish. Loricariids would easily differentiate white and black PVC pipes, but the authors don't mention if they standardized the internal coloration of their caves. I simply raised that point to note that they don't specify if they controlled for tint, a potentially confounding factor. While zebras do live in fairly deep water, to suggest that they don't see visible light makes little sense when they respond to visible light and most fishes that have eyes that we can maintain in the aquarium see in visible light wavelengths. Of course, visual pigments in loricariids have not yet been tested for their spectral sensitivity.

Furthermore, I don't see how recording a fish that can see in infrared with an infrared camera is different from recording a fish that can see visible light with a normal camera. This is assuming fish can even see in the infrared. Although some animals have been shown to be able to detect infrared (most famously are snakes, but one fish has been shown to do so), as far as I know, visual pigments like cones and rods have not been shown to have adapted to detect infrared. Deep-sea fishes are adapted to low light conditions, but have not been shown to detect infrared. Most fish can't even see red light, and it is common practice to use red lights to observe fish during the night. This is supposedly part of why many deep-sea fish are red; they are invisible! Furthermore, red light is quickly attenuated in water anyway, quickly becoming undetectable except at close distances.

very interesting thanks sucker for that information.

[antec]

Note: I enjoy discussing biology with you suckermouth, bouncing ideas back and forth gets the blood flowing in the brain:)

I haven’t read any studies on the anatomy and physiology of the eye or, to be more specific, the cones and rods. This is because I had no purpose to do so as of yet, I’m a brain guy. Could you post some articles on this, I’m very interested now since we’re discussing it.

Nocturnal animals are usually identified with their characteristic large eyes that enable them to capture the little light that is present in their environment. By observing the H. zebra, it seems to not have large eyes relative to its body thus giving me the idea that they do not capture light, or at least not significantly enough to indicate their need to utilize that specific characteristic. Perhaps the anatomy of H. Zebra eyes contains high concentrations of rods that will allow them to differentiate the levels of brightness in their environment. As for cones, I will confidently state that they have low concentration or sufficient capability to detect visible wavelengths. I mean an organism that is lives in an environment that is dark on a constant basis would not have the ability to adapt to a stimulus that is not present in their environment. (please note: I was incorrect when I stated that red light may be seen in those depths, I meant blue – I get confused sometimes with colour frequencies).

While zebras do live in fairly deep water, to suggest that they don't see visible light makes little sense when they respond to visible light and most fishes that have eyes that we can maintain in the aquarium see in visible light wavelengths. Of course, visual pigments in loricariids have not yet been tested for their spectral sensitivity.

I would have to disagree; I believe it does make sense. I believe they can see the intensity of light when it is turned on but to differentiate from its owner wearing a coloured shirt, or that the plants in the tank are green would most likely not exist. Despite their transfer from a dark environment to a bright aquarium environment, adapting that quickly to visible light is not plausible – maybe if they spawn numerous generations I suppose they would slowly adapt. As you said, “visual pigments in loricariids have not yet been tested for their spectral sensitivity” so debate on the matter is up in the air.

As for infrared, I have used an infrared camera to record fish at night and I have found that fish that live in well-lit environments do not react to the light, but nocturnal or fish that are found in low light react as soon as I turned the camera on. This was not an experiment but just an observation after reviewing the footage.

[Suckermouth]

I haven’t read any studies on the anatomy and physiology of the eye or, to be more specific, the cones and rods. This is because I had no purpose to do so as of yet, I’m a brain guy. Could you post some articles on this, I’m very interested now since we’re discussing it.

There's quite a lot out there. There are a number of papers looking at reef fishes and cichlids, and I'm sure other fishes as well. I can't say I'm an expert on fish anatomy and physiology but I'd say I have a passing expertise. I don't have a lot of papers off hand but I know that the literature exists...

Nocturnal animals are usually identified with their characteristic large eyes that enable them to capture the little light that is present in their environment. By observing the H. zebra, it seems to not have large eyes relative to its body thus giving me the idea that they do not capture light, or at least not significantly enough to indicate their need to utilize that specific characteristic. Perhaps the anatomy of H. Zebra eyes contains high concentrations of rods that will allow them to differentiate the levels of brightness in their environment. As for cones, I will confidently state that they have low concentration or sufficient capability to detect visible wavelengths. I mean an organism that is lives in an environment that is dark on a constant basis would not have the ability to adapt to a stimulus that is not present in their environment. (please note: I was incorrect when I stated that red light may be seen in those depths, I meant blue – I get confused sometimes with colour frequencies).

I would have to disagree; I believe it does make sense. I believe they can see the intensity of light when it is turned on but to differentiate from its owner wearing a coloured shirt, or that the plants in the tank are green would most likely not exist. Despite their transfer from a dark environment to a bright aquarium environment, adapting that quickly to visible light is not plausible – maybe if they spawn numerous generations I suppose they would slowly adapt. As you said, “visual pigments in loricariids have not yet been tested for their spectral sensitivity” so debate on the matter is up in the air.

Agreed, it is up in the air.

I will note that when I said that loricariids can "see" visible light, I meant that they could perceive the presence of light. Distinguishing color is different from simple detection of light.

I will also note that while it has been noted that H. zebra do live at relatively deep water to other loricariids, these are still depths that can be dived by people without much extra gear besides a snorkel (although some people hook themselves up to air pumps to extend the time they can stay underwater). Dark-adapted loricariids that have been discovered (Panaque bathyphilus and Hemiancistrus pankimpuju) actually have reduced eye size and white bodies, similar to cave-adaption in many fishes. The dark-adapted form of P. bathyphilus could only be collected by trawling, suggesting that these fish live quite deep indeed. I do not believe that Hypancistrus inhabits an extremely dark habitat, as eyes and coloration do not seem to match what we see in these loricariids that have adapted to such a life. The rarity of collection of dark-adapted forms might also be indicative of how deep they live; the dark-adapted form of P. bathyphilus was only discovered by trawling, rather than by diving, the latter being (if I'm not mistaken) the most common method of collecting loricariids for the pet trade.

As for infrared, I have used an infrared camera to record fish at night and I have found that fish that live in well-lit environments do not react to the light, but nocturnal or fish that are found in low light react as soon as I turned the camera on. This was not an experiment but just an observation after reviewing the footage.

The sensitivity of fishes to infrared light has yet to receive much scientific study, and I do believe that it merits further experimentation.