I have three mid-sized (about the size of a half dollar) mono argentuses in a 30 gallon cube tank. Over the course of two weeks, one has become very territorial, chasing the other two around constantly, even after I added all sorts of plants/hiding rocks. One of the monos being chased is now turning darker (which I gather means it is stressed). I added a few more fish - two small mollies and three green scats. Interestingly, the aggressor mono never bothers them, even when they swim in his territory. However, he continues to chase the other three monos. Any ideas on how to stop this or create some balance? Do I need to add some more monos? Or should I take the aggressor out? I'm afraid if I take the aggressor out, one of the other two will become aggressive...any suggestions would be very helpful.
Mono problems
- Thread starter davidsirota
- Start date
Woah! Your tank is way too crowded! Monos are schooling fish (5-6). They grow to a foot & will require at least a 300+g tank for a school of adults. Scats grow as large as a dinnerplate & will need at least 50g ea. Both require marine conditions as adults.
First off welcome to Aquaria Central! I do agree you are overstocked. The problem is Monos are active schooling fish that IMHO require at least a four foot tank (even when young, more of a 6-7' tank when adult) due to their schooling needs. Monos are extremely aggressive to one another when kept in small groups. The more Monos you have the more the aggression gets spread onto all fish and the less stressed they are. I would make a decision as to what fish you really like cause a 30 cube is not a great tank for Scats or Monos. If there is any way you can upgrade tank size and add more Monos that would help the issue. Definitely don't remove the aggressive one as that will create a worse situation for the remaining monos. Anyway, hope this helps and good luck!