I've been asked to post about my experience with briareus hatchlings.
A few years ago someone here in Dallas had a female briareus who had laid eggs. She wanted to share some of the hatchlings, so three of us were involved in the octo raising project. Debbie put a number of hatchlings in a large mature tank with no large preditors. The tank was also stocked with mysids. A second person took a number to raise in floating containers where they were fed individually with mysids. I took six day old hatchlings to for my mature 19 gallon tank, which had an abundant supply of copepods, mysids, amphipods, small snails and crabs.
Once put into the tank, they disappeared into the live rock. From time to time I caught a glimpse of one of them using a magnifying glass (they were tiny, fully formed octopuses from 1/4 to 1/2 inch long).
The other two people were not successful with their hatchlings, although the ones in floating containers lasted a couple of months.
So after about a week I didn't see any more, and over time thought they had all died. About four months later my husband was cleaning the tank and a little red octopus came charging out. We were both astounded. I had noticed that the amphipod population was reduced, that a few snails and crabs had died, but it never occured to me that I had an octopus in the tank. This tank was on the kitchen counter and we looked at it up close a number of times a day. Never saw anything at night, either. So I must have had a very shy octopus, since it saw us every day and night and never showed itself.
I would have transferred it out to my big tank much earlier if I had known. But it continued to seem frightened and hide after making its first appearance, and in another week or two I found it had died - maybe of stress at having been discovered. I was very sad that the little octopus didn't live longer.
The photos show the 4 month old briareus, the mother Jetta with containers containing her babies,
and one of the babies in a betta cup.
Nancy