Digitate Hydroids

[Donya]

I've got digitate hydroids cropping up like mad in the last few days on a rock with some yellow zoos on it. The hydroids killed one polyp so far and are making most of the others stay closed. There are also some purple polyps on the rock that are fine so far, so it seems to be just the yellow ones that are getting fried. I'm not really sure how to deal with the hydroids...I've been attempting to smash them or pull them off but it doesn't seem to be helping much. The smashed ones come back later the same day and other new ones appear almost as fast. Does aggressive manual removal actually work or will they just spring back up constantly? Is there a better solution?

 

[SkiFletch]

Joes juice and a hypodermic?

 

[rhysiboy]

whatever you do do not damage them in the tank. i had about 4 and tried to scrub them off then i ended up wit about 20. After about 4 months theyve finally dissapeared. I think the best think oyu should do is take out the affected rock and scrub it off in some spair water, then spray it with some joes juices. There are not very many animals that eat hydroids and non to my knowledge

 

[Donya]

Joes juice and a hypodermic?

They're too small...I doubt I'd be able to get a hypodermic small enough. They're extreemly skinny...like less than 1mm diameter.

I think the best think oyu should do is take out the affected rock and scrub it off in some spair water, then spray it with some joes juices.

Wouldn't that kill the zoos though? They're right in amongst the polyps so I can't really target the hydroids without nailing everything else.

 

[SkiFletch]

Yeah, the zoos are a large problem. If they weren't there I'd advocate chilling the rock (say dropping it into a 60f bucket of saltwater for a minute) and then letting the hydroids fall off as they loose their grip in the chill. Same thing would happen with the zoos though

 

[Donya]

Would the zoos die, or just drop off? I could give them another clean/uninfested rock to reattach to. I lost another few polyps overnight...the rest are percking up since I went on the last mad-smash of hydroids on some parts of the rock. I won't be doing another smashing though after reading the replies here, that was one I did prior to posting.

 

[rhysiboy]

how nice zoas are they~? lol. i think you should jut ty scrubbing them off out of the tank wthout joes jices. just make sure you dont get any particles that go on the rock or youll have loads within a week.

 

[Donya]

I'd be amazed if they got a foothold anywhere else in the tank. The rest of the tank is dominated by white ball corallimorphs, which I have yet to see loose a stinging battle with anything. The hydroids have not been able to spring up anywhere near the corallimorphs, which is probably why they're sticking to the zoo area. I don't want to wipe out the zoos just to nuke the hydroids, since I don't have any other polyps in that tank or any other tank. The rock also has a lot of small feather dusters and sponges and things on it that so far arn't being affected.

 

[SkiFletch]

Would the zoos die, or just drop off? I could give them another clean/uninfested rock to reattach to. I lost another few polyps overnight...the rest are percking up since I went on the last mad-smash of hydroids on some parts of the rock. I won't be doing another smashing though after reading the replies here, that was one I did prior to posting.

TBH, I dont know Donya

 

[Donya]

I lost about half the zoos on one side of the rock, but the situation seems to have improved. The zoos dying from existing hydroid burns attracted the attention of the bigger bristleworms in the tank, which in the process of eating the dead zoos seem to have eaten the digitate hydroids in the area too. They basically picked the worst part of the rock clean of everything. I can't currently see any more hydroids, and the remaining zoos are starting to open up again...all of the purple polyps are still intact and open. Some yellow ones still look a bit unhealthy, but there are at least a few left that are opening up when the lights are on. I'm doing daily small WCs to make sure the dead polyps won't nuke the tank.

 

[Donya]

So much for being hopefull...they're being attacked by something else now. Looks like individual hydra-like things rather than digitate ones...am pretty sure it's not digitates again since I've seen these other things before and they stay as a single polyp, but I've not had them in this tank previously. They're growing ON the yellow zoos, which i don't think I can do anything about. The zoos are showing discoloration where those have shown up. Oddly the purple zoos on the same rock are fine...I'm wondering if they're somehow contributing to the decline of the yellow ones though since they seem to be opening up more as the surrounding yellow polyps shrink back.

This stinks...the yellow zoos were all doing well and multiplying quite fast prior to the digitate hydroid attack

 

[Donya]

Well the yellow polyps finally got had a while ago by whatever those things were growing on them and a 2nd spring back of digitate hydroids in the area where they were holding out. Those seem to be completely gone now, although so are the yellow polyps The few purple ones are now multiplying in the area. I'm not sure what they are and I can't find my big corals book to ID them (this is driving me nuts but I doubt I'll find easily any time soon). They're bright metallic green when they open up but are not very big; the largest ones are ~0.5cm stalk length. At any rate, since they're all budding now and starting to recolonize the rock, do I need to think about target feeding them even though they're so small, or will they do ok from the particulate scraps that escape the white ball corallimorphs during feeding? I feed the corallis about once every week to week and a half on mashed frozen mysis.