A list of species that are and are not good hitchhikers.

[Sk8r]

You can get pix of these on the internet. Google the name.

GOOD:
1. nerites, stomatellas, limpets, conchs, chitons, abalones, cowries---in short, most anything with antennae and a snail foot is good.
2. bristleworms, spaghetti worms, peanut worms.
3. sponges of all colors and types.
4. mushrooms (if you DON'T want them, best just remove the rock to the sump and trade it. They get prolific.)
5. various corals. Again, some can be prolific. ID them and decide.
6. brittle stars
7. some shrimp. But avoid the coral bandeds: pretty, but may nosh on fish that sleep on sand.
8. eggs on your glass: usually they're snails and desirable. But if they're eggs on your zoas, they're probably nudibranchs, and they eat zoas.
9. little clams, barnacles, etc: probably won't live, but they're ok.

BAD:
1. most any crab, particularly hairy ones. They're fine in the sump/fuge.
2. unplanned mantis or pistol (loud click): fishkillers,
3. starfish (except linckias, which beginners should avoid, anyway: they will starve in a small/new tank.) Starfish either eat what they shouldn't, or die easily and shouldn't be in the CUC.
4. green serpent stars (fishkillers) fine in sump.
5. eunicid worms (tentacles on head) fine in sump.
6. any algae with roots. Can take your tank and is awful to try to get rid of. Not ok in sump: most can get through the pump.

Not a total list, but at least it will give you a start on what's a good find and what should come out. When in doubt, get it into your sump, where you can find it again.

 

[BrianKC]

This is a great list with one exception; the pistol shrimp is often maligned but is generally not predatory. Last week I witnessed mine gently remove a hermit from his burrow and deposit him safely back outside, turning on his tail with a loud SNAP of his claw as a warning not to come back inside.

 

[T Haynes]

I got a reef lobster as a hitchhiker...was a pretty good day! Along with stomotellas and bristle worms

 

[Sk8r]

I had trouble with a tiger pistol, who was amiable down to the day he began taking out tankmates. I don't know what triggered it. Fishy critter/inverts do respond to things like oxygenation, temperature, or whatever. I saw a massive tank of piranha who had lived together for many years turned into a mass of fish chowder. This, at the National Aquarium. I'm very glad I was not there for the actual event.

My point being that they can be a threat. We pair certain types of these creatures with appropriate species---which helps assure tranquility. Or we can set up specialty tanks to enjoy them where they're fed scheduled meals. The candycane or tigers are quite handsome creatures. Peacock mantis are gorgeous. I can certainly see why people are fascinated by a creature that can actually produce a plasma with his punch.

 

[T Haynes]

I had trouble with a tiger pistol, who was amiable down to the day he began taking out tankmates. I don't know what triggered it. Fishy critter/inverts do respond to things like oxygenation, temperature, or whatever. I saw a massive tank of piranha who had lived together for many years turned into a mass of fish chowder. This, at the National Aquarium. I'm very glad I was not there for the actual event.

My point being that they can be a threat. We pair certain types of these creatures with appropriate species---which helps assure tranquility. Or we can set up specialty tanks to enjoy them where they're fed scheduled meals. The candycane or tigers are quite handsome creatures. Peacock mantis are gorgeous. I can certainly see why people are fascinated by a creature that can actually produce a plasma with his punch.

was thinking about getting a pistol shrimp until i saw your post the other day. ill just stick with my watchman

 

[Sk8r]

Some people have great luck with them. I figured his doing in the watchman must've been an anomaly until he took out two firefish (they often try to go into the rockwork at night). He also took to making frequent loud snaps after dark. I wondered if he'd reached a point of trying to get a mate and the YWG was in his way...

I do know that, with some crabs like the mithrax, one gender is more prone to cause problems than the other, but I can't remember which gender. So maybe success with some of these shrimp depends on which gender you happen to get. Or if they transit in gender. Dunno. If somebody knows, I'm curious.

But darn! I was really fond of that watchman!

 

[T Haynes]

I like my DWG now that the sand is settling in my tank and he's got his dens set up. Pencil urchin has taken to one of them but that hasn't seemed to bother him. Every bodies happy so I don't plan on introducing something that may cause an issue. Although I will say I think one of my clowns has fish aids or something lol. He is generally always locked in an s shape but he does just fine right now when it comes to eating and everything.

 

[TimeConsumer]

More bad:
1) Nudibranchs; specialized and only eat one thing, sometimes that's your corals.
2) Aiptasia and Mojanos; Really annoying
3) Colonial Hydroids; Can take over if left alone

 

[Sk8r]

True on those. Nudis are particularly bad with zoas. Dip kills them, but not the eggs. This is why you need to hold zoas for observation over several days and use a magnifying glass. Things travel on what they eat.

Aiptasia, etc. Two critters will control them---juvvie peppermint shrimp, and (caution with corals and nems) the matted file fish. WHo is real easy to catch, a plus. Mine is doing well with euphyllia coral, peaceful with other fish.

Hydroids: there may be a cure for this if you catch it on one rock only, but I will not post it generally for fear someone will misapply it. PM me.