AHH!....Red Planarian Flatworm (Convolutriloba retrogemma)

[mooner]

I think this what I just snagged from my sump. Too small to get a pic but it is very small, dark green, red dot (mouth?) and is pretty darn quick. I saw him last night on my glass and read up on him today. Luckily he was in the same spot and I got him. I can only assume there are more.

It is about the size of a few pinheads so I can't get a good pic. It is the color of most common green algae or a common household plant.

In Sprungs "Invertebrates, A Quick Reference Guide" page 84, these little boogers are listed as pretty bad news if they proliferate and they are said to proliferate very fast and are "toxic to fish".

What should I do?

 

[mooner]

Hmmmm. Now I have spotted a bristleworm! It is in my sump as well. I know these are bad news only if it is a fireworm and good otherwise. Please, advice on both. Here is a photo.

I am doing a search now.

 

[Robin Goodfellow]

hi.
The "fire worm" probably harmless, unless you like to put one in your palm and squeeze it. The flatworm can be a real pain to get rid off... do a search and see what other people do about the flatworms. Good luck.

 

[wade1]

Just to clarify... the worm is probably just a bristle worm, which is harmless. True fireworms are not common, but they do eat corals. I have not yet (in many years) seen one in someone's tank.

The flatworms are mostly a pain for the owner of the tank. They can get very high in density and will make the tank look bad, but other than that, I have seen no real issues with them. I have heard it claimed that they can block the light from corals, although I sorta doubt this from my personal observations. There are chemical treatments that are claimed to work. Some livestock will eat small quantities of them (which works if you can't really find many but definitely does not if you have piles of them). Search the board for flatworm or planaria and you'll find piles of information from those who have had to deal with them.

Wade

 

[Marrowbone]

Yeah, regarding flatworms- I've always gotten the impression that they are the most harmful (and this would be true of many corals in your tank) when they die and release their toxins into the water. If you have a large population of them and they suddenly crash, then there is trouble. None of your fish are going to eat them, which is why they can multiply to unsightly and (potentially) dangerous numbers.

It's funny, they look slow because they look almost like a slug and they never really move much but when you try to siphon them out and you touch them they can really move fast.

I recently infected my tank with them, and I just try to siphon out the larger patches of them every now and then, so far no problems.

 

[Anonymous]

Yep, I have had red flatworms for years, in fact almost every reefer I have known with a tank up over a year has them. I have never had any real problems with them. Once they got to plague levels and were covering the sand in big red sheets. I would siphon out what I could from time to time, but the last few years they have just remained a sprinkling aroung the base of rocks in low flow areas.