want to get a mr. aqua 12 gallon that is approx. 36x9x9 and put 3 black plexigless dividers with holes in it so i would have 4 sections and keep 1 damsel in each section. without a sump, how would you do a good filtration method?
I thought of using a magnum 250 canister and rigging a return spray bar into each section.but i don't know if that would be enough flow. any ideas for simple filtration and flow.?

Just have the water exit one end and enter from the other end. Since you will have holes (slots are better and eaiser to make and for flow) from one holding cell to the next one you can have the water flow that way as well.

why are you putting dividers? just let them pal around together, damsels will shoal/school and it's fun to watch... that's really half the fun of the suckers...\

most of your filtration will be achieved by your liverock and sandbed.

really you don't need a lot of live rock, just get a little live rock and live sand, and plenty of foundation rock and sandbed, the live stuff will seed the non-living substrates.

a canister filter is fine, but really you could probably just use a hang-on-back cheapo filter... i like the kind with the biowheels, especially for a small tank where ammonia spikes would be a big problem.

my first tank was a 20H, all I used was LR and LS with the smallest Marineland HOB biowheel filter they make, which was like 15 bucks... I had several fish, corals, inverts all thriving with just that for filtration, zero nitrates zero phosphates.

why the hell do you want to keep damsels? lol as my sig notes. the evil fish should go to hell where they belong!!! lol muahahahhaaha good luck though:)

I just bought a 20H to house damsels. For your enjoyment, they will be fed to my wartskin angler.