voici ce que est dit ici http://www.worldofseahorses.com/dwarf%20basics.htm"Hydroids and other hazards
Even with a proper setup and appropriate tankmates there are more threats to these tiny seahorses. As you setup your tank you will want to be sure you are prepared to deal with these hazards.
HYDROIDS: Hydroids are present in most marine tanks - in small numbers they are not very visible and are mostly unnoticed and of no concern to most marine aquarium keepers. However, when large amounts of brine shrimp are introduced the hydroid population can expand very quickly and the sting from a hydroid can kill even an adult dwarf.
Hydroids come in a few varieties. There are the tiny jellyfish looking ones.. when swimming they appear to be jellyfish and when on the glass they are described as dots with legs.. a center dot with 8 or 9 tentacle dots in a circle. There are the cobweb looking ones... usually attached to the glass or objects in the tank but sometimes free-floating - these are very fine strands. I've also heard of a "pink fuzzy stuff" type but I have never seen these.
Fenbendazole (Panacur) kills hydroids. Panacur is actually sold as a dewormer for pets or livestock but is usually impossible to find locally. You can buy it and other medications from http://www.seahorsesource.com. What I did was set up the tank and cycled it, added everything I wanted in it then dosed the 3 days with the last day being the day I added the dwarfs - since my brood stock was to be wildcaught and they often bring the hydroids with them. Captive bred dwarves should be hydroid free. You can treat with the dwarves in the tank. Panacur will not harm the biofilter, fish, macros, pods, or shrimp. Panacur will kill some types of snails (particularly astrea), fans, worms of any kind, most if not all soft corals, gorgonians, all stars, etc. The effect on these creatures can last over a year.
There is a lot of hydroid/panacur information at www.seahorse.org - a search there will give you all the known details."
sur ce site http://www.syngnathid.org/il y a aussi plusieurs post assez alarment sur ces bestioles.
Donc voila je cherche a m'en debarraser.
