Decomposing Fish/Shrimp inReef Tank

[wattson]

Curious to know what the general make up of released elements of a fish/shrimp decomposing into the water column if left in the tank ?
As for elements like Ammonia/Po4 and any other pollutants could be released that we should be concerned for....

 

[Logan A.]

Curious to know what the general make up of released elements of a fish/shrimp decomposing into the water column if left in the tank ?
As for elements like Ammonia/Po4 and any other pollutants could be released that we should be concerned for....

Just as a reference there is a method of fishless cycling that involves letting a piece of shrimp create huge amounts of ammonia to get everything going and its ammonia not ammonium so it stinks.

 

[Randy Holmes-Farley Verified Community Expert]

A few comments.

The first is that, in terms of things released to the water, it really doesn't matter much if a chunk of fish or shrimp is eaten by a fish, or rots on the bottom. Most of the nitrogen and phosphate in it will end up in the water. People mistakenly assume that if a fish eats it, these mostly go into the fish, but that isn't true. So in the sense of elements released tot eh water, there's no more real concern about a rotting chunk of shrimp than if living fish had eaten it. (that said, there may be other reasons to not want to have rotting shrimp, from being unsightly to driving bacterial growth that may not be desirable)

The second point is that a chunk of tissue (fish, shrimp, whatever) will contain nearly every element and will release them to the water. Some will be taken up by the bacteria and other organisms growing nearby, and some will get to the water column. These elements include a lot of N and P, but also all trace elements required by organisms. There will also be a lot of release of organic molecules that will end up in the water and/or be consumed by other organisms around the tank system.

As to being "concerned" about the release of elements, I think it depends on the size of the fish or shrimp decaying in relation to foods typically fed to the tank. Imagine suddenly dumping in more than the usual amount of fish food. What would happen? If it is a lot larger than the foods given over the same time frame of its decay, then it will substantially jump the release of things such as ammonia and the bacteria in the tank may not be able to adjust in time to keep ammonia adequately low. Release of N and P and trace elements may also spur algae and/or cyano.

 

[wattson]

Greatly appreciate your input,,what would you consider to be the most beneficial element released from the decomposing shrimp/fish that would soft corals like zoas/palys be ?
If there were enough Po4/No3 in the water already.

 

[Randy Holmes-Farley Verified Community Expert]

Greatly appreciate your input,,what would you consider to be the most beneficial element released from the decomposing shrimp/fish that would soft corals like zoas/palys be ?
If there were enough Po4/No3 in the water already.

Is there a reason to think there is a benefit?

All photosynthetic organisms need a whole bunch of trace elements, and a shrimp will contain all of them. Which, if any, is beneficial depends on which ones are deficient in your tank.

It will also release organics, and possibly bacterial, which soft corals may consume.

 

[wattson]

Is there a reason to think there is a benefit?

All photosynthetic organisms need a whole bunch of trace elements, and a shrimp will contain all of them. Which, if any, is beneficial depends on which ones are deficient in your tank.

It will also release organics, and possibly bacterial, which soft corals may consume.

Yes,,I think there are elements that are beneficial.
I have been driving NO3 down to lower levels in my system to try and start dosing Urea..No3 was in the mid 20s and now around 8 per Red Sea No3 Pro test kit.
I have set up an experiment tank separately from my mainsystem to start dosing Urea/Ammonia to see the effects on some zoa/palys.
As of now its been 4 weeks since this experiment tank has cycled and seems to have stabilized on params since a week ago.
So,,I already moved some zoas/palys over to the experiment tank, but no dosing just yet.
I shouldnt say this but Im sure Ill get some ridicule from this but,,I have bought some raw shrimp from the food store and have been putting pieces of shrimp in a net in front of a power head leaving it to decompose to release its residue into the water column..
Been doing this for the past 2 weeks and removing it only on weekends.
No smell what so ever..
I have not seen No3 (8)rise and Po4 (.05) has been stable with use of GFO.
I have experienced nothing but good things so far,,great polyp size and very good growth compared to any foods Ive fed before...

 

[Randy Holmes-Farley Verified Community Expert]

You may be feeding them bacteria that come off the shrimp.

 

[BootyPup]

That is a pretty interesting experiment, I have always viewed corals like that to like their surroundings dirtier. There is just more to feed on in my opinion. Especially how you are doing it.

 

[wattson]

I just put a new piece of shrimp in the net yesterday ..it doesn't take long ,the next day to see corals all plumped up and looking like the are enjoying what ever they are getting off of it.
Possibly a bacterial feeding plus what ever other nutrients from the decomposing shrimp are doing something positive it "Seems"..
Ill keep doing it til things progress to a negative topic arrises..
Hopefully monday Ill start to dose Urea and the dead shrimp idea in the experiment tank and see what goes on ..Planning to do a large water change to lower Po4/No3 as much as I can to start the experiment with good low base numbers in these 2 categories..
Especially when I have no way to test for Urea levels so far..Plan on going slowly and watching other params first to see if there is any other relationships with urea..