I have them in two spots in my 34g. They have been there for going on two years and have never spread. I dont get the impression that they are easy to kill! Ive covered mine completely in a thick layer of epoxy and after several weeks they simply sprouted through the epoxy. Ive also heard mixed things about these guys.
Before we get too far into Hydroids, how did you go about IDing them as Digitate Hydroids? Is there any way you can get an image of them.(If your camera won’t focus perhaps a video of them will be easier.) If no image perhaps you could link to a photo you found online and tell us “this is the closest image I can find to what I have” and describe any differences you notice. Do a google image search of Spaghetti worms and vermetid snails as well and compare.
If your tank is indeed follow you will notice TONs of animals reproducing in numbers they never had before. It is as if your whole system is a refuge for these critters with out the predation of fish you had before. The extra food present will even further their rate of reproduction.
I believe you are correct in slowing the food to an almost stop. The serpant stars will be able to find lose food and hardly need to eat anything at all. In a week or two you could add a little bit of food a day. Perhaps go with half of what you would feed when your tank was stocked with fish and of course continue with water changes and any media changes and other maintenance as you would normally. The idea is to keep the aquarium going healthy just as if there was fish present, or get it to healthy conditions if it wasn’t already. If you feed and do water changes like normal there is no dramatic nutrient change when you add the fish.
As far as hydroids go I don’t have a lot of experience, but from what I do know they are very hard to identify. Some are harmless, some are harmful. I have heard a kalk paste, similar to what you would use to kill apitasia, is the way to go for removal, but before you try it lets see if we can be more sure of what it is. Do they form tight little colonies or are they spread apart in random clusters? Seen any show up in the sand or grow on your power heads/pumps? Are they present in dark areas of the sump or mostly in high light areas? If you can get a clear image it will help.
While we are at it what sort of fish and animals did you have in the tank before? Do you have a stock list yet you plan to add?
Hope we can help.
Shawn I too had something in one of my tanks I had roughly IDed as hydroids. I was never sure and they never seemed to spread. I eventually ended up breaking them off the rock and discarding them. I haven’t noticed them any more, but then again they are in my Xeniidae and anemone tank, so you can’t hardly see the rock in their.
Seems like your right on with the ID, but I have to admit I have 0 hands on experience with these guys. At this point my best advice would be to read up a bit more on them, ask some true experts for some opinions, but then make a personal decision.
Seems as if you’ve got 50/50 odds with these guys. If you keep your system a low nutrient system there is a large chance their numbers will shrink. It doesn’t appear as if they are going to hurt any of your fish or corals, but might bother you while you’re working in the aquarium. They aren’t really desirable and if removal was easy it would be highly recommended, however since you mentioned you already have a significant number of them it seems like you have two options.
- Let them be, and see what happens.
- Fresh water rinse the whole system, get a couple of pieces of new rock and start from square one.
It is totally up to you it seems. If the system was running with fish and corals I would say let it be and see what happens. However since the aquarium is already going follow for disease it might be a good time to rid yourself of them and start over from scratch. If you don’t think it is a well established system, if you don’t have that much rock at all in it… it’s up to you.
I would highly recommend posting in this forum for some opinions, Invertebrates; Morphology, Ecology, and Behavior – by Dr. Ron Shimek While it isn’t a very busy forum many of the frequent posters are from the scientific community and might be able to give you a bit more information.
Ron Shimek, “I can’t really predict competitive outcomes with corals. That will vary with coral involved. In most cases they don’t seem to bother corals, but they will live on them. To them the coral is often just one more colored rock in the vicinity.
As far as I know, nothing imported for the hobby will eat them.”
Image and info: (example of someone that seems to have had them and had no issue with them)
http://www.melevsreef.com/id/digitate_hydroid.html
Wish I could be more help. If you want to shoot some ideas through us or discuss it further feel free.
Jumped the gun with this one! Saint:) Saw hyrdroids and assumed it was the typical variety that plague hobbyiests. Jon is more the oddball critter guru! lol
I had a lemonpeel angelfish once that LOVED hydroids. They (Dwarf Angelfish of the Genotype Centroype) are pickers… but they do sometimes pick at things you dont want.
What type of hydroids did you have?
Not 100% sure… its before I was any good at ID’ing hitchikers.
They typically give a nasty sting if you touch them, so it’s surprising to hear something goes after them. Not surprising though, for every animal in the ocean there is more then two that will eat it. Nature finds a way.
Knowing the pygmy or Centropyge angelfish it wouldn’t surprise me if they would sample Hydroids that had more of what reefers would think of as a polyps shape. AKA the ones that resemble zoanthids and protopalythoa which Centropyge angles are known to occasional sample.
Don’t happen to have any old images of the hydroids barried somewhere do you Bellamy?
Nope, lost the computer that they were on. Thats back when I used to grow lettuce sea slugs, back in Maine. I belive that you are right in that they were the ones shaped like small yellow polyps almost.