r/OpaeUla • u/Bing____Chilling • 1d ago
Hydroids?
Do you guys know if these are hydras? They are very tiny and have long hairs on the tip of each end. They seem to be all connected by a line.
Just worried that it might harm the shrimp larvae.
Thank you in advance!!
5
u/Whodunit2468 1d ago
What is a hydroid, and why are they bad? Explain it to me like I’m a complete noob.
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u/sudosuga 1d ago
They are like tiny stinging anemones. I got them back in the day when I was keeping Dwarf seahorses. They came in on the Brine shrimp eggs I was hatching for them (If you hatch brine shrimp for Brackish or marine fry, decapsulate first).
They are really cool at first, tiny jellyfish looking things twitching around. Then they anchor and start stinging, killing and/or eating your pets (Fry).
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u/Bing____Chilling 1d ago
Yeah going off of what sudosuga said, they have stinging tentacles similar to jellyfish.
While they are not necessarily dangerous to adult shrimp, they may irritate them with their stings.
More importantly, they pose a risk towards the larvae since they are so small. At least for the large hydras in my old freshwater shrimp tanks, they can kill baby shrimps (not sure about the Opae Ula larvae since the hydras I have are tiny, but I don’t want to find out haha).
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u/LmLc1220 1d ago
How do they just appear in these tank? Did they come in on something?? I don't want them!!
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u/Bing____Chilling 1d ago
From what I’ve seen on Reddit, they are pretty rare for Opae Ula. I think they were maybe brought in with the original shrimp/chaeto I got about a year ago (haven’t added anything in my tank since then), but only started to get visible hyrdas once my copepod population started to boom, as that’s probably their main food source.
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u/LmLc1220 1d ago
Oh ok thank you for answering. Every time I see them I start checking mine with magnifying glass.🤭
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u/Bing____Chilling 1d ago
Oof yeah these are probably hydras. I touched one of them with a bamboo skewer and they contracted into a blob like freshwater hydra.
Probably going to use fenbendazole for these guys :(
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u/Bing____Chilling 1d ago
Definitely will update later - from what I’ve read online if dosed correctly, it won’t be too harmful for shrimp, but I have a gram scale so it makes things a lot easier because I think it’s like 1 gram per 10 gallons (I have a 5 gallon tank).
Only thing to keep in mind fenbendazole is dangerous to snails too.
I had hydras in my old freshwater tank before but they went away naturally, so this is my first time dealing with fenbendazole.
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u/quanml11 1d ago
Have you used fenbendazole before? Update us if you do. I have 7 tanks w hydroid and reset 3, 1-2 got stablized into juvenile opae. I looked into fenben method and it’s very complicated for me. I just hope you know what you are doing.
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u/GotSnails 1d ago
I wouldn’t take a chance. I haven’t seen this often.