[Octopus Eggs]: Trapper's Babies - Tank Raised Mercatoris


Staff member
Moderator (Staff)
Sep 4, 2006
Cape Coral, FL
I decided to journal Trapper's hatchlings on a new thread (see [Octopus]: - Trapper - O.mercatoris for the mother's journal and the hatchlings first 12 weeks). Another journal ends the experience with the last two surviving grandchildren.

Recap summary:

The Mercatoris hatchlings (does anyone know the proper name for octo babies and at what point I should call them juveniles?) began being born March 17th. Over a 5 day period, only six babies hatched. During the first week one died after climbing up the net about an inch above the waterline and apparently could not find its way back into the water. The remaining five are now approaching 13 weeks old (I changed the breeding net to one that is larger and has no netting out of the water). They rarely leave their current shell dens (but do change shells on occassion) and lie in wait for small shore shrimp and pipette fed Cyclop-eeze. Two of them will occassionally hunt the lower side of their partitioned net. In addition to the shrimp and Cyclop-eeze I have provided sailfin molly fry, snails, new hatch brine, pods and live mysis (brine, pods and mysis for the first 3 weeks only and in combination with Cyclop-eeze). The fry and snails are surviving very well on the Cyclop-eeze but the octopuses have no interest in the fish or snails as food. It is appears that they ate the brine, possibly the pods and always the Cyclop-eeze.

So far, there has been no cannibalism but they are very well fed. I have recently twice found one shell firmly secured to another occupied shell but neither octopus seems to have damaged the other. I have also seen squabbles over the use of a particular shell. I keep the shells at least an inch apart and so far, everyone is alive. I plan to add a couple larger shells this week to try to avoid more arguing :roll:

The net is open topped to the water but none have ventured out into the main tank. Since Mercatoris are nocturnal, it is difficult to photograph them and impossible without a flash. They do not appear to be concerned with the flash and remain visible after my attempts to capture them on film (well, electronic media).


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If you look more closely (and use your imagination) you will see two arms and two eyes in the shell in the lower right. I wish I could get a shot of one of them out of the shell. They really do look like octopuses and have really grown a lot but they started out much smaller than the cuttlefish. Both are about an inch total length, including arms. The cuttles are ready for their first tank (15 gallon) but the octos are no where near ready to hunt in the 45. It is easy to understand why we don't see these as juveniles from the wild.
:shock: oh, I can see the two arms coming out of the top of the shell, I can't make out the eyes. I can see the eyes on the left because there is more light there, hence more contrast. probably real fun trying to hold the camera still long enough to get a shot without using the flash (I know you didn't want to cause 5 little ( well 15 little :cool2: ) heart attacks.)
Actually I DID use a flash, the reddish cast is the red LED that is on 24/7 but it is impossible to get a picture otherwise. Stangely enough, they don't react to it much at all (I do tilt it to point just over the netting to avoid reflection and minimize the brightness on the octos). I intended to start flashing the camera every night at feeding time so they would associate the light with food but they really have not reacted to the brief light. The most difficult part is feeding them with one hand to try to get them to come out and trying to shoot with the other :hmm:. One in ten are in focus.
Mercatois babies 17 weeks

Trapper's five little offspring are still growing. I am still feeding cyclop-eeze nightly with a pipette. The catch some of the live shrimp in the net if the shrimp come close enough to their dens but I don't see them out hunting now and all but one actively show feeding posture when I squirt Cyclop-eeze into the net to announce feeding time.

I still have all five in the same net and intend to separate them soon but have to admit to being a bit lazy about going ahead with the plan. I am seeing two and sometimes three of them creating "doors" from some of the extra shells. Occassionally one will use a shell housing another but so far we have had no known fighting. I do, however, separate the shells when I see this happening and is the primary reason I think I need to split the group. Three of them have been more interactive with the feeding tube (they will grab it and "climb" up with their den's attached) and had decided to put these three together and leave the more recluse ones together but one of the more recluse ones is now also reaching for the tube and insisting on "more food, NOW" (my interpretation of the grab and climb action) behavior so I may wait until the fifth one shows the same confidence before I split them. They are still nowhere near ready for a large tank and my hand feeding may delay their release for quite a while.

I am still worried about how to transition them on to larger food. They continue to grow so I know they are getting nutrition but I have no knowledge of how much they should be growing and thus can't tell if I am underfeeding them. Roy has posted an observation stating that cutting back on food for tank raised octopuses may have a positive impact on longevity but did not include any hints on quantity or age so I am still pretty much shooting from the hip.

I can't tell them apart except by their choice of dens. One has the den behavior of it's mother and only exposes one eye while the others tend to come out enough to see both eyes when they feed.
Mercatois babies 21 weeks (4 months)

All five babies are still in their breeder nets (now split into two groups). Up until tonight I wondered if they would ever leave their shells and explore. I do not want to release them to the tank until I am sure they can find food.

Earlier this week one of the shyer ones started leaving his den and staying out all night (and day but not day active). Tonight two others (as well as the original venturer) were out of their shells for at least an hour. I stuck my finger in the net and touched one. The one underneath the platform reached up to touch me and spooked the one I was touching so we had a brief inking but the surprised one did not go back to his shell and we played a little touch me game for a few more minutes.

None of the three were frightened enough by my fingers to go back into their shell but they were not overly please with the flash when I tried to photograph them. The pictures are pretty miserable and I took a number where the octopus saw the camera before I could get even close to focusing and all I filmed was shell:hmm:


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Mercatois babies 22 weeks

The octo that stays out of its den for as long as a full day is beginning to interact in a non-aggressive way! Two days ago it was exploring the lower section of the net so I moved my fingers around on the outside of the aquarium and it responded with an arm wave. This was a definite response and not just coincidence. Several times this week (tonight included) I have wiggled my finger inside the net and it will reach out and GENTLY touch my finger. Tonight we played touch me for about 10 minutes. I ended the game when it blew on my finger but I came very close to being able to touch its mantle and hope to progress to that with this one. So far, none of the other 4 have been this receptive.

In the other net, I have one that is agressive (the one that tried to separate my nail from my finger :cool2:). It is always the first in that net to come out for food and grabs at the pipette. If one of the others shows an arm, it will grab at its sibbling. I am planning to move the two in the other net (they seem to coexist very well as you will note in the attachment) into their own aquarium tomorrow and will put the aggressive one in a net by himself.

The attached picture is taken at night with a red light. To the eye, both octopuses appear to be white, only with the flash can you tell that one is showing brown coloration (interesting since they are in an almost identical environment).


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Something that might be fun and interesting to keep in mind as you're observing these kids is at what age they start showing various behaviors. There's an interesting report in Hanlon & Messenger (p.145-146) showed that hatchlig Sepia officinalis couldn't learn to stop attacking shrimp behind glass, but adults could, which suggests that some brain capabilities, in cuttles at least, develop further with age... it would be interesting to compare your mercatoris hatchling observations with the batch of bimaculoides Zyan will hopefully have shortly! I'm not sure what the analogous experiment would be for an octopus, though. But it's interesting to consider the difference between brain development needs in octopus hatchlings, which are "on their own" from the beginning, as opposed to humans, which get care, food, support, and instruction from their parents. Maybe young cephs have more instinctive behaviors so they can fend for themselves as their nervous systems develop, while mammals just have instinctive tendencies to accept what their parents give them.
I have thought along similar lines and is one reason I had asked Carol when Biddle started to socialize. With 5 it will be interesting to see if the others follow the same behavior pattern as my interactive little guy or if they remain more recluse. One of my reasons for keeping this journal is to MAKE me record my observations at the time rather than just trying to remember.

After I recorded our interaction last night, I played with him a little more later that night (early in the AM). He is definitely interacting with me and not trying to eat my finger (unlike the aggressive sibbling) and is not showing fear. I want to put two of them in the other tank but am somewhat afraid I will lose the contact in the more open environment. I could move the two in the other net but since this little guy wants to explore I keep thinking he would be happier in the larger aquarium. My parameters are not quite equal so I may wait a week to decide ...

Wishy-Washey Momma
I put two of my kids on the bus

Well, OK, maybe it is not their first day at school but I put them into their first tank. I have been delaying this but decided I really needed to move the more agressive one into a net by himself so my best buddy and his net mate went into the 15 gallon tonight. Film at 11:00 - well maybe more like 2:00 AM and on PhotoBucket since they are too long for direct posting.

Well, maybe tomorrow. It seems PhotoBucket is very slow to upload and convert tonight.


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Here is one, I don't know if the others will upload or not:

Photo and Video Storage | Photobucket

This is the little guys first experience with rock. He came out several times and just felt the LR with his/her arms. The other one disappeared into the live rock and I have not seen anything but arms coming out for food since.
Cute little guy!

Please be sure to send this to Tony (tonmo) so we can keep it in the gallery - I'd hate for this one to disappear!

Unfortunately the stills are not clear enough to keep for posterity and the videos are too long to download to the site. I am trying to get the best of the videos into photobucket now (I can do a direct FTP for pictures but the videos have to be loaded from their download program and converted - takes forever). The listed video is the second best and I have loaded a longer but not as clear one but the longest one really shows him/her touching and examining the LR for the first time and is actually fairly well focused.
Video of First Day In Tank

I finally got the longer and best of the videos of this little guy's first curiosity about his new environment up to my photobucket site (too long for direct TONMO load).

Photo and Video Storage | Photobucket

There are actually two octopuses in this tank but the other one (always shy) has taken up a home in the LR and only shows its arms. Anyone know a good name for a creature that is ONLY arms? These little guys are over due for a name.

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