any ideas on what this is

[chefjamesscott]

So I was doing some maintenance on my 180 sw which is basically rock and fish only. I purposefully killed off all the coral because I did not want to spend the time or money to keep them alive for the tank here. They were basically a bunch of mushroom and polyps that came with rock from other peoples tanks that I bought.

Well today I noticed about 5 places in the tank where this stuff is growing and I was wondering if anyone had any idea what this might be. The texture is similar to that of a facial sponge and it can be pulled off the rock. I just wanted to see if anyone had any idea as to what this was.

I also found a couple of crawlies on the bottom of the piece so I thought I would take a pic of them too.

a very fast moving starfish

and a pod.

I am glad to find the crawlies because I know the tank is healthy. Yet, I am very curious as to what this white stuff is.

On a side note, I was doing some filter maintenance on my home 75 and in the filter media I found a bristle worm on one of the bio cubes. only 2 inches long so I threw it in the tank.

 

[Kevin8888]

So I would say that the "white growing" stuff, would most likely be a sponge, or possibly a tunicate (aka sea squirt), both are good as they show your tank is healthy. I know you didn't ask about the "crawlies" but I figured I'd throw in my 2 cents worth. The first as u mentioned is a mini star, specifically mini serpent star, which is wonderful to see in your tank as they are a wonderful addition to the cleanup crew. Though it is possible that they are just baby serpents which isn't bad either just means free tank mates haha. The pod appears to be of the amphipod variety one of the bigger types of pods.

 

[boldtogether]

It looks like a sponge to me. Just watch it. It kinda looks neat.

 

[Gprime]

4th pic is an amphipod my tank is crawling with them, my spotted green mandarin loves em.

 

[Reefbuff01]

I would say it is a sponge - definitely a sign of a good, healthy tank. If you don't want them though you can surely remove them by pulling or scrapping them off.