How many damsels?

[fish123234]

I want to stock my 20 gallon high with some damsels. I have around 20 pounds of LR, clean up crew, ect.... I am planning on starting up my 10 gallon sump with more live rock, a refugium, some sand, and probably about 4 gallons of water. For water movement I have 2 power heads, a HOB, and hopefully the sump outlet. I am also keeping a few corals, galaxy, green cloves, and frogspawn. I was wondering how many damsels would be ideal. I don’t want to overstock, but I want to fill in the empty space. As far as the type of damsel I am interested in the "convict" type and the solid blue or yellow tail variety. any suggestions?

[pinchyboy]

The thing with damsels is that they are really agresive towards each other. I think you will be able to put 3 damsels max and thats pushing it. To be safe i would only have 2 because with 3 they might stress themselves out or kill eachother

[Goodbye]

I would suggest to only keep a single specimen in a 20g tank even though keeping a single specimen will likely increase the damsel's teritorail behaviour. It is best to have a group of 5 or more, but a 20g tank is too small for that number. Make sure you include plenty of hiding spaces for fishes to seek refuge in.

[kaybee]

The thing with damsels is that they are really agresive towards each other....

They can also be aggressive toward other things in the tank, like other fish newly added corals or even your own hand when you're doing in-tank maintenance or adjustments. My two azure damsels have no qualms about biting the hand that feeds them.

Additionally, damsels can have a tendency to dig (nothing like coming home and seeing your lower-level corals covered in sand as a result of damsel-digging.

My damsels seem to hate any new corals (which to them are just objects that 'weren't there before') and seemed compelled to knock over or push out anything added after them.
I think they should be added after everything that will be in the tank is already in the tank.

Also be aware of how large particular damsel species get. Some stay small and max out at 2" or 3". Others get way larger (5"-6").