Clear critter on firefish

[SaltyCrew4u]

Just noticed a small clearish almost flat looking critter on firefish. It doesn't look like a worm, a little to round. To difficult to get a picture. It almost skims across its body. Any ideas?

 

[aislin809]

Parasitic copepod, or sea lice as they are called.

 

[SaltyCrew4u]

Parasitic copepod, or sea lice as they are called.

Should I worry? If so what could I do?

 

[ISpeakForTheSeas]

Should I worry? If so what could I do?

Yeah, if it's a parasitic isopod, you want to get rid of it, but they may not cause too much damage:

I wouldn't expect these to kill a fish, but, yeah, if they're attaching to a fish, that's a parasite, and you don't want it.

They generally do die out on their own, but it seems it may depend on the exact species; as mentioned in the ReefKeeping.com article above, they sometimes reproduce even in tanks without fish (thankfully it's not common though), so some species may be facultative detritivores/carrion-feeders or able to feed on other critters that come in with live rock (such as other pods, worms, tunicates, etc.).

Anyway, yeah, remove any on the fish, and if you want to try removing as many in the display as possible, there's not really any harm in doing so as long as you don't just leave food in there for them indefinitely - like the article (which covered most of the removal methods available) mentioned, pull any bait before leaving the tank for an extended duration.

https://reefkeeping.com/issues/2006-02/bp/index.php