Dr. Ron, are these flatworms beneficial or a plague??? ....

[Newreeflady]

I am trying to do searches and such, and found an article you linked....

Many of the really small flatworms are herbivores that eat diatoms and other microalgae (Palmer 1988). These are rather common in my aquaria and I suspect in the aquaria of other hobbyists. However, I have not seen any from other tanks. An aquarist might consider them a useful auxiliary herbivore to control these algae, but the worms are too small and eat too few diatoms per day to really be of much benefit. On the other hand, they probably would not be detrimental to the reef aquarium system in any way.

The flatworms I have are really small, the smallest would probably be 3-4mm, the largest 1/4"?? They are yellowish translucent colored, with a tiny red what I think is a mouth, or I guess maybe a balancing structure? They are kind of hourglass shaped, and I just noticed them 2 days ago, and can now spot them in many places amongst the rockwork and glass.

So, are these beneficial in that they eat microalgae? Even if so, will they take over my tank soon? Do you think I should add some type of blennie to keep the population under control?

Tank is fairly new, but cycled, see signature for info on the tank. I have several small colonies of assorted corals, should I be worried about the flatworms bothering/injuring them? They are definitely on my green star polyps.

Thanks so much!
Angela.

[rshimek]

Originally posted by Newreeflady

Hi Angela,

The flatworms I have are really small, the smallest would probably be 3-4mm, the largest 1/4"?? They are yellowish translucent colored, with a tiny red what I think is a mouth, or I guess maybe a balancing structure? They are kind of hourglass shaped, and I just noticed them 2 days ago, and can now spot them in many places amongst the rockwork and glass.

So, are these beneficial in that they eat microalgae? Even if so, will they take over my tank soon? Do you think I should add some type of blennie to keep the population under control?

The animals you have mentioned may or may not be a problem, they may be the "red planaria (http://www.rshimek.com/rogue's_gallery.htm#Red%20Planaria) which can be plague. These pests may range in color from gray to tan to cherry red - so color is NOT a reliable cue. You need to use a magnifying glass to see if you can see if the tail end of them has three small bumps (lobes) on it - one on each side and one in the middle (compare to the photo on the link).

If the three lobes are present, do a search in this forum (link at the top of the page) using "red flatworms" or "red planaria" as the key words and you can see what people have tried to do to control them. Fish generally do not eat them. One slug does eat them, but is an unreliable control. The only sure-fire treatment that kills them is a chemical called "Oomed" and it has problems of its own (see the threads on flatworms for a discussion of this).

So... the bottom line is that I can't tell you what worms you have. You will have to determine whether or not you have some that are harmless (2 lobed tails or tails without lobes) or a problem (3 lobes). If it is the former, I wouldn't worry about them. If it is the latter, I would indeed worry - and contemplate a course of action from your readings.

Good luck! :D

[Newreeflady]

Thank you sir, i'll grab a magnifying glass and check one out tomorrow, hope I can catch one:D

Much appreciated,
Angela.