sponge id

[codyreed29]

I found this sponge growing under a rock. Weird purple color looks pretty cool.

The thing is I had this rock in a tank for about 1 year and never noticed it until recently. do sponges go dormant and come back in optimal conditions?http://i57.*******.com/20aqo1l.jpg

This rock was in my ten gallon I feed on a strict reef chile diet and good frequent water changes and appeared. ?I think its cause the chili and zoo phyto plank

[codyreed29]

I aslo have a brownish yellow sponge growing on another rock with a hole in the center about 1.5 cm thick.

[TimeConsumer]

I can't ID it, but they're pretty common. My refugium had a ton.

Sponges absorb silica from the water column and if it gets depleted they will start to fade away. So they tend to disappear from a lapse in water changes and reappear after water changes (or silica dosing) resumes. More information of silica and sponges here: http://www.advancedaquarist.com/2003/1/aafeature1 Sponges are filter feeders so a regimen of micro food such as phyto will keep them growing.

You also tend to find them in darker spaces as sponges aren't photosynthetic and have a harder time competing with algae in well-lit areas.

[codyreed29]

thnx time consumer a good read I hope.