Hmmm, what is this?

[Valkyrie]

I have probably 8-12 of these rather odd, almost cocoon looking, things. Some hanging from a pump, a few on a powerhead and even some on the heater bracket. It's really difficult with my phone to get a picture that is clear and better focused. If needed, I'll get my DSL out for a few shots.
I tried to get one close up and one that showed a little bit of perspective. These things are all about 1cm tall with a base that is about a 1/2 cm.
They look easy enough to remove if necessary.
@Lionfish Lair I didn't see them in hitchhiker guide, if I missed them let me know!

 

[ReeferMaddness843]

Looks like pineapple sponges

 

[ReeferMaddness843]

Not my photo, did a quick Google for reference pic. Look about like this?

 

[Valkyrie]

I think so! Yea! Mine are a bit more conical, but I'm pretty sure those are it. Thank you!
The best thing about this is that I thought to myself when I first started seeing them, "sponges of some kind?" but being new and all I doubted it. I must be learning!

 

[ageno125]

Not my photo, did a quick Google for reference pic. Look about like this?

Looks like pineapple sponges. How new is the tank? I had a bunch early on and they eventually disappeared on their own

 

[Valkyrie]

Looks like pineapple sponges. How new is the tank? I had a bunch early on and they eventually disappeared on their own

Tricky question. The life of the tank started about 4 years ago. I acquired the entire set up including livestock 16 months ago, the only thing I changed was the water and the sand. I had a heater malfunction this past August, killing all of the livestock. Restarted it in September. So this chapter is working on it's 8th month.

 

[ageno125]

Probably just part of a cycle then. Good sign though.. clean water!

 

[Valkyrie]

Well that's awesome. Thanks!

 

[Mark_C]

Pineapple sponges = happy tank