Hydra=Problem??

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COG Commando

Feeder Fish
MFK Member
Jan 19, 2011
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West Bend, WI
This might be in the wrong section, but hydras are invertebrates so... While admiring the roots on my Anubias barteri (I know, a little weird), I noticed hydras growing on the roots. They appear to be budding and I'm just wondering if these guys are going to be a major problem when they decide to explode (in growth). Any input would be appreciated as I will let them just live out their cycle if they won't be a real problem. I have no idea how they got in here either, as they must've been introduced as polyps somehow because I didn't think they had a spore/dormant stage.
Tank stats- 20GL Xenopus laevis
Ammonia, Nitrites, Nitrates - 0ppm
Temp - 79F

IMG_1398.jpg
 
Hydra don't have either a dormant stage or reproduce by spore. The anchored stage you're now seeing is a juvenile colony of hydroid organisms. These colonies reproduce asexually by producing 'bud' daughter cells. They also produce adult stage hydroids that are free-swimming medusae which reproduce sexually. These medusae produce eggs that develop into ciliated larvae called planula. These swimming planula seek out new anchoring points to develop into new hydroid colonies.

Hydra are predatory and incorporate stinging nematocysts in their tentacles to capture, paralyze, and digest prey. In aquaria, they're known to kill fish fry and invert larvae.
 
If you do wish to eradicate the hydra, Fenbendazole (a livestock grade intestinal antiparasitic) will work well and is safe enough to use in invert tanks. 0.1 to 0.2 grams per 10 gallons of tank volume should kill off all hydra within 24-48 hours.

Fenbendazole is occassionally found in the pet trade and is sold as Panacur and SafeGuard.
 
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