ID this in an abalone shell??

[Hordearii]

Can anyone help me ID what is on this abalone shell??

 

[WheatToast]

I think these are bryozoans, which are filter-feeders. I never had success with them in my temperate tank.

Bryozoans:

Is this a temperate tank?

 

[Hordearii]

Is this a temperate tank?

Tropical tank, this is on a haliotis asinina

 

[Hungrypede]

Liveaquaria pictures show similar to yours, perhaps a feature and not a bug.

Tropical Abalone Snail: Saltwater Aquarium Invertebrates

The Tropical Abalone (Haliotis sp.) is one of many healthy high-quality ornamental invertebrates available for your saltwater marine aquarium at LiveAquaria®.

m.liveaquaria.com

Its been about a decade since we could harvest abalone on the California coast, but if I recall they have similar feelers coming out of the top.

Where’d you purchase from?

 

[Hordearii]

The large wholes are normal, it's the network of small holes between the two large holes on the right that I'm confused about. This is from J&L Aquatics in Burnaby, Canada.

 

[ying yang]

Only a guess ,but some kind off eggs?
If so idk what,but could start by looking whats in your tank and research If lay eggs and if do what they look like .
Or really half guess = sponge but doubt it

 

[Hordearii]

Only a guess ,but some kind off eggs?
If so idk what,but could start by looking whats in your tank and research If lay eggs and if do what they look like .
Or really half guess = sponge but doubt it

This abalone was just introduced, nothing else that's been in the tank lays eggs, relatively new tank that just had trochus snails, but today added the abalone, 2 fighting conch, and 8 nassarius snails.

 

[WheatToast]

Is this a temperate tank?

Found a bryozoan that looks more similar:

 

[Hordearii]

Found a bryozoan that looks more similar:

Any idea if it has any beneficial or negative effect in the tank? Kind of creepy, but also cool looking

 

[WheatToast]

Any idea if it has any beneficial or negative effect in the tank? Kind of creepy, but also cool looking

Given that they are filter feeders, phytoplankton dosing might help to keep them alive. This article states they are relatively benign:
http://reefkeeping.com/issues/2003-10/rs/index.php

Somewhat unrelated, but these cool looking "bryozoan cups" sometimes enter the trade: