<a href=showthread.php?s=&postid=12415715#post12415715 target=_blank>Originally posted</a> by TikiDan
Maybe if people chimed in with personal expieriences on certain things like "I have a "_____" in my tank with no problem, or I tried "____" and this happened.
I will go over the fish that
I have personal experience with. This is not a comprehensive list, many species are not listed because I have never kept them.
Fish and other critters that I have kept, but have NEVER kept with seahorses, and NEVER will, regardless of circumstances, size of tank, or the specimen's personality (i.e. it doesn't matter if the reef crashed, if the fish was small, if the tank was huge, etc., etc. - its still a "no"):
Triggers, Tangs, Rabbitfish, Lyretail Anthias - they are all too fast of swimmers, too aggressive of eaters, and too territorial.
Corynactis/pseudocorynactis (jewel anemones) - have the ability to kill seahorses (I
have unintentionally kept these with seahorses - it did not turn out well - one got to a seahorse before I spotted it in the tank).
Various hermit crabs (halloween, zebra, blue leg, red leg, scarlet) - if I
had to choose, I'd choose a scarlet, but I don't plan on ever keeping hermits with my SH. Not just for the sake of the SH, but also for the sake of my snails, which I need to keep my SH tank clean. Plus, when weighing peace of mind with any benefit hermits might have, having peace of mind wins.
Fish and other critters that I have kept with seahorses, but will NOT keep with them again. These are a personal judgement call, and I am ONLY going by my own experiences:
Peppermint shrimp - they were fine when they were small (heck, they were afraid of being eaten), but as they got larger, they got bolder. They would climb into the feeding dish and steal food, climbing over the seahorses to do it. The seahorses became reclusive and ate less, and I never saw the clown goby anymore. Once the peps were removed, the seahorses and clown goby became a lot more active again. This was a gradual thing, and I almost didn't notice, and pretty much just removed the peps on a "hunch".
Gorgonians - my female seahorse likes to rearrange the decorations. The macros can handle being picked up and dropped all over the tank (or in some cases, the seahorse trying unsuccessfully to pick them up), but the gorgonians never faired very well with this treatment. If she was able to move the gorg to the sandbed (where she moves everything

), the gorg ended up laying in the sand until I noticed, sometimes with macros dropped on top of it. This is not good for a gorg. If she was unsuccessful, the wrapping of the tail and tugging irritated the gorg. This is also not good for a gorg.
Live rock - this is a test of my patience. I do have live rock in the tank right now, but I won't add any new live rock to my system; only dry like marco rock. After a while, you get sick and tired of keeping up after all of the hitchhikers - and the only sure fire ways to remove the hitchhikers also remove all the reasons why you get LR in the first place. It can be a danger, but it is more a test of my patience, and I don't want to bother with it anymore.
Things that I have kept with seahorses, that I would recommend:
Yellow clown goby - great tankmate, does not bother the seahorses or compete with them; but is very skittish, even more so than the seahorses, so having any bold tankmates may make the goby a very boring tankmate. They are a cute and active addition when kept soley with seahorses and/or with slow, passive tankmates.
Various macro algaes - treated to remove nasties like aiptasia of course.
Kenya trees, feather dusters, nassarius snails, astrea snails, nerite snails, cerith snails, fighting conchs, limpets, stomatella, spaghetti worms, spirorbids, etc. - of course, with proper qurantine of anything purchased or aquired (i.e. anything that didn't spontaneously appear in the system).
*There are a few fish that I keep that fall into the "well, if the tank crashed..." category, or that I would try based on the individual specimens personality and the
exact specs of my seahorse tank. However, I know my seahorses, I know how to I.D. normal
and stressed seahorse behavior, and more importantly, I have been keeping the specific individuals seperate from my seahorses long enough to know whether that particular individual
might be okay. These fish were not included on the list, because you have no shot of getting my specific individuals. The fish listed under the "NEVER" category, would never fall into this range of "maybe".*
HTH