Schooling Fish Suitable for Angels

Byron

This is not recommended. Jack Wattley, who knows perhaps more about Discus than anyone, having caught them, raised them, spawned them for more than half a century, has often written that angels should not be combined with Discus. His primary reason is that angels are more aggressive at feeding than Discus and can (in his experience) often out-compete them. While the Discus may eat, they may not, or may not eat sufficient, or even if they do eat may still be stressed by the ordeal of having to overcome the angels.

Byron.

iamgray

I've got 5 angels and 8 harlequin rasboras in a 67g planted tank... the rasboras tend to stick together for the most part, and the angels pretty much ignore them. However the angels are still very small (bodies are just larger than a quarter), so I can't really speak for what might happen once they are fully grown.

noledoc

Byron, one of the questions I keep coming up with as I anticipate putting together the > 500 gal tank, (which I plan to kind of compartmentalize into smaller zones), is this; how does that vast increase in tank size effect the compatibility of fish? The information about these two species is helpful but I wonder about the effect this size tank has in all kinds of ways. I know we tend to think about the aquatic world in terms of much smaller sizes. Your thoughts? Kym?

Byron

There is no doubt that the larger the tank, the better many fish species will fare. But one must remember that it is still an enclosed system, and fish that would avoid each other in the wild are unable to do so in an aquarium. Fish secrete pheromones into the water; this is one issue with water changes, to remove some of them regularly. Other fish may or may not pick up on these, depending what they are for and the particular fish species. It is now known that shoaling fish communicate chemically; characins are especially adept at this. And the chemical signals secreted by some species are only caught by that species, or at any rate, other species seem to ignore them. This is one reason why chemical substances are so risky in an aquarium, they can interfere with some species' natural chemical releases.

I would argue that regardless of tank size, "compatibility" in a community of fish is always the same issues: water parameters, environment, behaviour. The latter is what we are somewhat discussing here, and while the larger tank may allow for more flexibility, there is still the fact that fish read things the way nature programmed them. If a Tiger Barb is sending out chemical signals about aggression, even if the other fish are able to stay out of its way due to a large space the signal is still being read. And that means stress. And stress means health issues are more likely to occur.

This is why one cannot place much trust in "appearance." For an aquarist to say that the barbs and angels are living well together is an unproven statement, because the aquarist cannot possibly know what is going on in the mind of the fish in the aquarium. It does not have to end in actual physical violence to be a problem.

Byron.

noledoc

Byron,
Thank you again. Do you offer preceptorships for those of us who know so little? You have a way of introducing relevent information without being dogmatic.
Do you know whether the chemical signals are all or mostly of danger and stress or is it possible that some of them are of a positive nature? The kind that signal, "This is a nice place to hang out."
As you know, in the human species, these chemical signals have mostly been replaced by vastly enhanced visual and auditory signaling that is mostly available for subliminal pickup.

Cpt NAPA

[quote=Byron;532407
This is why one cannot place much trust in "appearance." For an aquarist to say that the barbs and angels are living well together is an unproven statement, because the aquarist cannot possibly know what is going on in the mind of the fish in the aquarium. It does not have to end in actual physical violence to be a problem.



Taken from the above information I would expect that the compatability recomendations in the profiles on this forum are not to be taken as correct as the person or persons that submited the profiles have no way of getting in to the mind of the fish. However, since we need some parameter to gauge the acceptability keeping different species in the same aquarium we will have to accept the recommendations of those that have observed the interaction of the various species in captive situations such as we intend or simply forge ahead blindly and see what happens. Cpt NAPA

noledoc

Cpt Napa,
I've found Byron to be exceptionally helpful. To take a well meaning meatphor out of context and use it to take a swipe at someone so wise and generous with his time, isn't quite as gracious as a simple thank you.
Just a thought.

Cpt NAPA

Excuse me Byron. I didn't intend to sound ungracious in my reply. I have been following this thread since it started and thought that the original question was about keeping schooling fishes with angels in a 400g aquarium.
While I find the thread to be quite informative and thought provoking in presenting different ways of looking at the origanal inquiry, we have thrown a monkey wrench into the entire compatibility issue.
For as long as I can recall compatibility was judged on the probability of keeping fish of multiple species or single species in an aquarium in seeming harmony. Sort of like keeping a group of kids together without them tearing each others hair out. Most all books from Exotic Aquarium Fishes onward include a short snopysis of compatibility of each species. They are based on observed behavior. However having said that I again apologize for voicing my thoughts with out thinking. It is
your thread noledoc. Cpt NAPA

noledoc

Cpt Napa,
I think you raise a very interesting question and I'm very glad you're getting involved. I think your message to Byron was very appropriate and helpful. Best wishes.

Byron

According to research and published findings by Dr. Stanley Weitzman and his colleagues, and various other highly-qualified ichthyologists, the chemical signals cover many areas. Obviously danger is one, but also food. Hans Baensch wrote of how one can scatter food on the surface of a stream in Amazonia, and characins are invariably the first to find it en masse. Dr. Weitzman also studied reproduction and there are chemical signals for this. It is also said that smell is of more importance to many forest fish than sight in feeding. I inserted some info on this in another thread recently, how fish have taste cells not only around the mouth, but on the skin covering the head, flanks and in some even fins. This is closely related to chemical identification. I believe second to chemical is the auditory perception; fish has very high "hearing" capability, greater than humans in fact. Their "ears" achieve this but also the lateral line system of receptors.

Briefly on the issue of compatibility, Dr. David Sands, an authority on catfish especially the Coryadoradinae, did some experiments (I believe for his PhD) on defense strategies of Corydoras. Even the presence of a dummy predator (made of wood) caused panic in the fish. Nature has programmed so much into the fish's physiology and instincts that we should attempt to avoid situations where such responses are triggered by the presence of unsuitable fish.

Byron.