Orange Sponge doing badly

[jack.pe]

Hi,

I have an Orange sponge (compact kind, not branching) I bought around two weeks ago and it looks like it is doing pretty badly, developing some grey black areas.. does anyone have any tips?
When I bought it originally I cut a bit off it for a friend so the sponge was out of the water for arounf 4 mins while I cut it, would this have damaged it?

It is ina rea with good flow but not massive flow i.e not directly inf ront of a powerhead but with good water movement.

 

[aninjaatemyshoe]

Air exposure can lead to trapped air bubbles in the sponge, which can kill parts of the sponge. These kinds of sponges often also need to be fed a good amount of phytoplankton or bacterioplankton. All in all, there are a number of things that may be causing your sponge to decline. Most decorative sponges aren't easy to keep, most die in captivity.

 

[OwenInAZ]

I'm pretty sure that most sponges either can't tolerate being out of water, or at least hate it very much. Could be the problem.