Sponges 101

[YungNeil]

Hello all,
This is my first post, and I am start out by asking a few questions about owning a sponge. So here you go:
1) Where can I purchase a pet sponge?
2) What do sponges eat?
3)What kind of tank will it need?

I also read online that if you take the sponge out of the tank, it will die because the oxygen in the air will get captured in the holes of the spong, is this true?

Also if their is other knowledge that I need to know about sponges, please post them.
Thanks in advance!

 

[Donya]

There are sort of two categories of sponges in the trade: hitchhiker species that show up on live rock and larger ornamental species. The hitchhiker species tend to be quite hardy if they aren't eaten by animals, but they are also considered boring or even pesky in some tanks. In contrast, the larger specimens that are brightly colored and more classically sponge-looking are VERY difficult to care for.
 
All sponges are filter-feeders, and for many species we don't know exactly what they are consuming. Many sponges fail even in mature systems that have some degree of natural or artificially enhanced food source in the water. Additionally, some sponges of the ornamental sponges sold in the aquarium trade contain toxins that can kill other animals in a tank if the sponge starts to decay, so be aware of this risk if you are adding the sponge to a tank that already has other animals like fish in it. Smaller sponges of the type that hitchhike in on live rock do not seem to have the toxin issue from my experience (unfortunately the flip-side is that many animals like to eat them!). 
 
 
 

1) Where can I purchase a pet sponge?

 
Sponges show up both by accident on live rock shipments and as larger, ornamental specimens in the trade. Some saltwater specialty stores carry the ornamental sponges regularly, others only by special order and some not at all.
 
 
 

2) What do sponges eat?

 
Some combination of find particulates and microorganisms suspended in the water. This page is worth a read on the subject:
 
http/www.advancedaquarist.com/2011/6/inverts2
 
I have many small sponges growing in my tanks because I dose them with a combination of phytoplankton and other small particulates. Some I've read also absorb a lot of nutrients more directly. However, when you dose a tank like that, it can be challenge initially to keep the water quality high enough to support sponges - they require a very stable, healthy environment that is also rich in nutrients, which is a precarious combination for a small body of water.
 
 
 
 

3)What kind of tank will it need?

 
Aside from the small, hitchhiker sponges, larger sponges do best is large, mature reef systems with a lot of biodiversity and often some sort of phytoplankton dosing system to artificially boost the microorganism populations in the water. So, if your primary interest is just the sponge...it would be difficult to the point of being a bad idea to set up a tank just for a single ornamental sponge specimen. On the other hand, if all you want are some pineapple sponges, although they are very tiny they are hard as nails in systems that are nutrient rich and might be possible to keep easily in a small desktop tank or something similar.
 
 

I also read online that if you take the sponge out of the tank, it will die because the oxygen in the air will get captured in the holes of the spong, is this true?
 

 
With many sponges this is the case. Some of the smaller, hardier species like pineapple sponges and other hitchhiker species can tolerate some degree of air exposure - which is why they survive being transported on damp rock that usually just wrapped in wet paper. However, ornamental sponges should definitely be kept submerged. Even when I need to move a rock that has hardier sponges on it, I always take the precaution of keeping it submerged just to be safe. 

 

[YungNeil]

So can I keep a few pineapple sponges with a ball sponge and a tube sponge?

 

[Donya]

What size tank do you have or are planning to set up? Pineapple sponges can survive just about anywhere (provided the water has sufficient particulates and nutrients) but other varieties not necessarily. If you try to have too many sponges in too small a tank, supplying enough food to prevent starvation without sacrificing water quality is problematic.