I have a orange tree sponge in my tank for a couple of weeks now and really have not seen much activity from it but i did not think much of it till tonight when i decided to feed live baby brine shrimp to everyone hoping to excite my clown pair when my sponge when nuts for them lol sticking out all these white tubes from all over the branches some were about 1/2" long. i just thought it was cool never expected it to do that over shrimp.