Help, are Blue Dolphins (Cyrt. moorii) very aggressive??

[bamboofish]

I have three blue Dolphins, only about 2", and I think they killed off the remaining Zebra.
All I had in a 20 gal., was the 3 dolphins, a zebra, a kribensis, and a pleco all small.
Anybody know if they are very aggressive?

[elk]

I`m not an expert on cichlids but isnt a 20g too small for this many cichlids.

[nissannx]

way too small for chiclids period. not sure if they are aggresive but that many fish in that small space will cause agression. i think minimum for chiclids was 40-55 gal?

[bamboofish]

They are only small, under 2", and were way more crowded before. That is only 1 fish per 4-5 gal.
They were less aggressive when I had 20 fish in there....
Is it the breed, that is nasty???

[elk]

you had 20 in there,and now only 5 hmmmmm

[synodontis]

I have 4 malawi dolphins in a 125 gal tank.  They are not aggressive by cichlid standards, but due to their size, they can hold their own with most of the less aggressive cichlids.  I have never seen them pick on another fish, except when breeding - even then, they just chase any intruder away.  Be aware though that malawi dolphins do get big.  I have had mine for about a year.  Purchased a year ago at 1 inch, 3 of them are now about 8 inches long with about a 4 inch height.  Curiosly, my 4th dolphin is only about 4 inches long - purchased at the same time.

[whanrow]

I have one in a 30 with many other cichlids with no issue.  In fact it is the least aggressive in the tank.

In that tank are single fish of the following:
julie - transcriptus
cobalt blue zebra
ps elongatus
ps demasoni
about 4 others I can't remember right now
synodontis petricola
synodontis multipuntatus
2 giant oto cats

No aggression, no torn fins, no problems. Lots of filtration, lots of rocks.  The dolphin is the biggest in the tank - 4.5".

[rechaud]

you can consider to buy a bigger tank if you want to keep your moorii 
Dolphins get huge and they are not peacefull fish and as the day pass, they get bigger and bigger, they will start to have more agression and that agression will be higher if the other dolphin are males or if you have 2-3 male for 1 female. Also, in a small tank, the territory are smaller so they will try to have there own place in the tank but if the tank is to small they will fight for that precius space. I have a lot of dolphins in my 125 gal and can tell that in the end, i only keep one because my dominant male was to agressive with other moorii.

Like some other guy said, you need at least 55 gal if you want to have a nice colony of cichlid without having any problem. When you are dealing with cichlid, you have to deal with agression and need to spread that agressivitie by putting a lot of fish in the tank. Thats the main reason why you need a respectable tank size. I don't say your tank is to small, but i think its not enough big if you want to keep moorii. You will have to sell them in 5-6 months because they will big just to big 

good luck and enjoy the cichlid world 
réchaud...