[soverjas]

have a small issue with hydroids. They seem to be decreasing in numbers over the past two weeks. Having never had them before I read up and found that the kind I have are common. Just kind of ugly on the glass. I found this pic online of the kind it looks like I have. There pretty small I am wondering if a shrimp would clean them up.

 

[allendavant]

Oh, so that's what those are! I had them on the glass of my 7 gallon a while back and had no clue what they were. Are they bad?

 

[steve52]

They're a type of jellyfish, and they can sting your corals. Kalk paste will kill them.

 

[Jessemac]

It appears that some types of Nudibranches will eat these. But, from what I am reading there are many types of Hydroids and some more aggresive than others. Here is one like I have found that lists two species by scientific names. Still looking for common names on these at the moment.

The Sea Slug Forum - Hydroids

 

[soverjas]

Yes there are 100's of kinds of hydroids. The particular one I have from what I have read are more or less harmless unless there numbers grow enough to cover large surface areas and that the tend to be in most systems but in small numbers. They tend to grow in population when there are nutrients in the water column. Which with the new system only completing its cycle a few weeks back that would explain the numbers I was seeing and now they are decreasing. just curious to if anyone has ever seen there shrimp picking at them. I would imagine they would.

Hydrozoa - Wikipedia, the free encyclopedia
Hydroid - Wikipedia, the free encyclopedia

 

[Jessemac]

Yes there are 100's of kinds of hydroids. The particular one I have from what I have read are more or less harmless unless there numbers grow enough to cover large surface areas and that the tend to be in most systems but in small numbers. They tend to grow in population when there are nutrients in the water column. Which with the new system only completing its cycle a few weeks back that would explain the numbers I was seeing and now they are decreasing. just curious to if anyone has ever seen there shrimp picking at them. I would imagine they would.

Hydrozoa - Wikipedia, the free encyclopedia
Hydroid - Wikipedia, the free encyclopedia

I would think so as well. Curious to which type of shrimp if so. I found a couple of threads on RC about them but, couldn't find any info as to what would eat them other than some types of Nudibranches but, the most of the ones mentioned were also said to eat montis, nems, zoas and the like.