Two fish questions

[elephantnose3334]

@Colin_T, I have two questions regarding fishkeeping. Do cardinal tetras live in massive schools (50 plus) like they do in the wild? I saw a massive planted tank from a TV show on YouTube which shows a massive school of cardinal tetras along with discus. It's a good tank but it's a pain to maintain. Another question is how do fish communicate with each other? I don't hear them all the time, just see them.

 

[JuiceBox52]

Yes, like all schooling and shoaling fish they do best in large groups, in captivity or in the wild

They communicate through body language, some fish change their colors when they’re stressed, ready to mate etc, and through chemicals (pheromones and allomones) that they release into the water

Some fish communicate using electrical impulses, like electrical eels, elephant nose fish, and ghost knife fish.

Very few fish make audible noises. These include croaking gouramis and squeaking catfish, and even sparkling gouramis can make noises

 

[WhistlingBadger]

Yes, like all schooling and shoaling fish they do best in large groups, in captivity or in the wild

They communicate through body language, some fish change their colors when they’re stressed, ready to mate etc, and through chemicals (pheromones and allomones) that they release into the water

Some fish communicate using electrical impulses, like electrical eels, elephant nose fish, and ghost knife fish.

Very few fish make audible noises. These include croaking gouramis and squeaking catfish, and even sparkling gouramis can make noises

Sparkling gouramis really talk things over. So do some of the botia loaches, especially zebras.

 

[GaryE]

The best cardinal tank I have ever seen had 3000 of them, moving like a choreography. I had 300 once in a heavily planted, big tank, and it was fantastic.

Communication techniques are diverse. Most fish have far better abilities to sense the world around them, especially to sense movement via their lateral line. They also have chemical signals, and in the case of cardinals, eyes.

 

[Seisage]

Very few fish make audible noises. These include croaking gouramis and squeaking catfish, and even sparkling gouramis can make noises

This could be a freshwater thing, since I know quite a few marine fishes make noise. I'm sure there are many other freshwater fishes that make noise, but I don't know as much about them. The drum is a notable one, as it's literally named after the sound it makes. They're found in both brackish and freshwater. The plainfin midshipman is also notable because it's apparently quite loud. Certain rockfish also make noises, as well as a ton of coral reef fish. There are a lot of chirps, squeaks, and grunts going on in general, but coral reefs are particularly noisy when they're healthy and have a high diversity of fishes!! Even though it's not a sound that they generate within their bodies, parrotfish make a lot of noise as they scrape away at coral. When I've been diving on reefs, it sounds like a crackling sort of background static to me.

 

[simonas]

Funny enough I have recently added 14 cardinals and 14 rummy nose to my 6ft tank. The cardinals are dotted all over and easy to count the rummys are the most tightly bunched mini shoal and move up and down in that shoal

 

[GaryE]

I think a fish like a cardinal, that spends time in a flooded forest, would need to be very visual. Even if they had sound, trees would interfere.

I've been able to break up Cichlid fights with hand motions imitating a much bigger fish coming to see them. Spread your fingers wide and wave them like a caudal fin, and they don't keep fighting til they see the rest of the fish. Moving a hand does nothing. but waving it like a male going into a challenge ritual sends them running back to their corners.