Tank size and overfeeding

[Gonodactylus]

On this and other lists I have frequently argued the need not to over feed and octopus and the need for stable large tanks. I just want to reenforce that message with a description of what happened to me over the weekend.

I have a large O. rubescens that we reared from a field captured juvenile. It is housed now in a 50 gal tank with canister filtration and the entire system is kept in a 15 C walk-in coldroom. The system has been running 9 months and is rock stable with respect to water parameters.

Last week couldn't find any live grass shrimp, the animals usual food, so I gave it a piece of frozen tiger prawn about the size of a golf ball. The food was quickly devoured and I thought all was fine. The next morning the animal looked distressed with rapid, heavy pumping of the mantle. It was barely hanging onto the side of the aquarium with just a few suckers. There were lots of feces in the tank and ammonia had spiked.

I used a fine net to remove all the organic material I could and did a 20% water change immediately with what cold water I had. By evening I had cooled more water and changed another 30 %. I didn't feed the animal for two days and I'm happy to report all is fine.

My point is that even if there isn't uneaten food in the system, natural waste from a big meal can over whelm a tank that is probably too small. Next stop she displaces a stomatopod from a 125 gal system.

Roy