Is this algae or a hydra

very nice colony established there. ;o)

ditto above.
 
Yep, they are so cool that I am looking for ways to rid the tank of them. They started out as 1 or 2 on a heater, and now I must have 100+ in the tank. I made the mistake of scraping them off the heater while it was in the tank. The floated around the tank and attached themselves to the plants, the sponge filter, the canister filter intake, the tank walls, and the plants. Now, I have a mess in my tank. If I had known they were hydra, I would have taken the heater out and scrubbed it down in the sink with some soap and water. What a PITA this is going to be.
 
Cutting back feeding & good gravel vacs should work but if you need a faster response or if that doesn't work check this out Dewormer to kill planria & hydra. Also google it & you'll find tons more results. I bought the safe-guard dewormer at DFS but have not used it yet. Good luck to you!

EDIT- Forgot to mention, excellent photo skills there! :)
 
Unless you're breeding fish in the tank the only place that Hydra are a problem is between your ears! Relax there are lots of worse things to worry about! They're easy to get rid of and harmless to all but the tiniest fish.
 
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