red bellies?

[ctenopoma]

what makes you so sure that your fish wouldn't be able to grasp the situation? Put it this way, if you walked by your tank, and every time you did you chased your fish around the tank violently with a net, i would give it about 3 days until they hid when they saw you. which in fact shows that they can learn and even recognize YOU from someone else. If they can show this level of thinking i wouldn't put it past them to have some type of emotions either, such as happiness and sadness, anger, and being comfortable. why do you think it takes such a long time for piranha to come out of there shell? probably because they are scared (which is another emotion) and need to become more familiar and at ease in a particular tank.. with that said, cramping your fish will leave them unhappy and stressed out, bad water quality leads to disease and a whole bunch of other problems... Not showing good colors and sickness are common side effects and your case will be no exception..

Thanks Joe, exactly what i was trying to say

I'm not questioning that they have these emotions , they do for sure , I'm just saying they can be easily distracted or forgiving ( like during feeding time )

 

[JoeDizzleMPLS]

there are different ways to stock your tanks and keep your fish happy and stress free, you can stock lightly, you can follow the 20 gallon per fish rule, or you can overstock (within reason) a larger tank. in my opinion, a 75 gallon tank is the bare minimum for multiple natts, you can throw three or four in there easily, they will set up their territories, and you can hope that there won't be any problems, but still no guarantees.

if you have a 125 or larger, you can follow the 20 gal per fish rule, throw 5 or 6 in there, they will set up their territories, and you can once again hope that there won't be any problems. if, however, you decide to overstock that 125 and throw in 10 or so, they won't have an opportunity to set up those territories so there will still be less aggression in the tank.

in a smaller tank, if they get overcrowded, they will literally run out of swimming room and you will run into problems, there will also be water quality issues that need to be taken into consideration, too many fish in a small tank will result in dirty water extremely fast.

pygos are also just fine on their own, alot of people are under the impression that piranhas are schooling fish and that they like to be with other piranhas so much that they will be unhappy and become stressed if they are put in a tank by themselves, but this is just not true. people need to do a bit more research on these fish before they jump on every person that has a solo pygo or is thinking about owning a solo pygo.

hope this helps... feel free to ask any other questions you have