DIY Parrotfish and Puffer Feeding Block

[Billtcat]

Recently purchased a nice Princess Parrotfish. Absolutely a gorgeous fish but I was concerned that I may not have enough active algae growth on my rock to keep it well fed. So I did a little additional research and learned that public aquariums use plaster of paris blocks similar to weekend feeders for their parrot fish and puffers. Both need a hard surface to graze on to keep their teeth from overgrowing. Here is what I came up with
Plaster of paris
Spirulina powder
Nori crushed and flaked
Commercial marine fish pellets

Mix up the plaster of paris but a little wetter than directed.
Gently fold in the other ingredients and pour in molds.
Molds can be ice cube trays, Styrofoam egg crates or whatever you like. I bought a container for craft items that has 2" X 1" compartments as I wanted bigger blocks. Will probably switch to the Styrofoam egg container as I had to wreck the box getting the blocks out?
After dried enough to remove from mold place in front of a fan or in my case I put them in my food dehydrator on low heat and completely dry. This can take several days depending on size.
Store in airtight container.
I put the first block and it has been very well received and lasted a little over a week. Now on block two, all the inhabitants take a peck or two at it but the parrot fish has been eating on it regularly throughout the day and looks fat and healthy. Puffer nibbles on it regularly too. Have not seen any negative effect on my water chemistry.
Just thought I would share

 

[karimwassef]

Is plaster of Paris reef safe? Wouldn't it disintegrate in water?

 

[salty joe]

That's a really interesting idea.

Turns out you can make kalk plaster as well as plaster of Paris. https://en.wikipedia.org/wiki/Plaster

Does this block get tumbled all over the tank?

The main thing that concerns me about things like this, including calcium reactors, concrete scapes, hydraulic cement, kalk slurry, mag replacement, etc., is the possible, probable? buildup of unwanted metals. I have all of these except for the calcium reactor and have plans to fire it back up. My next reef purchase will be Cuprisorb or similar.

 

[karimwassef]

The only issue seems to be a gradual imbalance of S but water changes can slowly fix that back.

 

[salty joe]

How would you know sulfur is out of whack unless you can test for it? I've never seen a saltwater test for sulfur.

 

[karimwassef]

you wouldn't. it's the only ingredient in plaster of paris that would drive the imbalance.