Originally Posted by MikeDay88
The Barbs only seem to nip at each other once in a while, nothing in the tank even bothers with the Cichlids, especially the Keyhole. I may get a couple more Barbs. But what else is different that I could put in with these. Like a birchir or crayfish or crab. And how many fish should I be able to home in a 44 gallon tank?
You are over the limit as is, due to the nature of some of the fish. Have you read the profiles? I think the Tiger Barb profile is pretty clear as to why you need 8 or more of this fish, and they would fill a 30g tank. You have a 46, so that is fine for the 8 TB, but if you start crowding them they will get aggressive [more on this momentarily]. The danio need to be increased to 6 minimum. Plus you have the two cichlid species (which I still feel is going to be trouble with those TB eventually).
The bichir will attain a foot, and should never be in a tank with anything that would fit in its mouth. [This might be the solution to your TB though...they would likely be gone before long.]
Crustaceans and mollusks are outside my knowledge base, so I will only say that i have read of crayfish eating fish.
Now to expand on the behaviour issue. Fish are the way they are due to how they have been programmed through evolution. We cannot change that. Science can tell us what may set these behaviours off, and that is now established fact: too few fish in the group, and too small a space (to the fish) around them. Too many other fish can have one of two consequences, increased aggression or just the opposite to the point of wasting away and premature death. Both are caused by frustration. The fish is lashing out at what it finds stressful, and in the only ways it knows how.
While fish can respond differently to some situations, there is a sufficient evidence that certain responses are far more likely in certain situations. The nippiness of the 3 barbs is only the beginning, but this is completely natural behaviours. All barbs, with a couple of exceptions, tend to be feisty, but in this species it is heightened a lot. Increasing the size of the group may reduce this, or it may confine it within the group. Putting them in a small space (a 46g is small to this fish) with other fish is stressing them, and they will likely turn on the sedate cichlids as easy targets.
All of us have learned about our fish over time, whether by example or by research. When we fail to follow the "norm" it may not come back to haunt us, but in most cases it will. There are enough members on this forum with direct experience of the possible aggression of this species and others to show that it does happen. I would carefully rethink your stocking. An aquarium of compatible fish is more likely to succeed, and that means greater enjoyment. Having to constantly battle disease (stress weakens the fish's immune system causing disease that woould otherwise be fought off) and removing dead fish and replace them is not enjoyment, at least not to me.