hydras and guppy fry - help!

This morning I noticed a hydra in my tank. It's pale-yellow, 2 mm long with
six tentacles. Now it seems the more I look for them, the more I find - some
are really small, less than 1 mm, some are larger. I even saw one sting a
snail when it got too close.

Anyway, the problem is, I have a breeder net in the tank with guppy fry of
various ages (about 20 in total). The fry seem to be all right, although its
pretty hard to count them.

It's a 20 gallon tank with live plants. Besides the fry, there are also a
pair of guppies, 5 neon tetras, 2 rasboras, and 1 rummy nose tetra.

One article on the net says hydras are no concern for livebearer fry - is
this true? If not, how do I get rid of them? I don't feed live food - just
tropical fish flakes. Is it a better idea to move the fry to another tank?

Please help, I really don't want to lose the fry.

Thusly "Jan" Spake Unto All:

One article on the net says hydras are no concern for livebearer fry - is
this true? If not, how do I get rid of them?

IMO hydras are no concern for pretty much any fry. I had literally
tens of thousands of hydras in a 10 gallon tank I raised lampeye,
killi, and rainbowfish fry in.
The biggest problem with hydras is that they steal food from the fish,
and eventually I tired of them. I raised the salinity to about 3 ppt
(that's 3 grams of salt per liter water, or about one large, heaping,
tablespoon of salt to 2 gallons). At first it seemed nothing happened,
but after two weeks the hydras were gone.

Guppy fry should not have any problems with 3 ppt salinity if you wish
to try, although some plants and apple snails wont like it.

There are other ways of dealing with hydra, but that usually means
using toxic chemicals like formalin, or medication like fenbendazol.

Originally Posted by Mean_Chlorine

IMO hydras are no concern for pretty much any fry.

I did see some one posting whose betta fry were decimated by hydras. I would think it also depends on how much other food it available, and the size of the fry.