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Normal Rate of Growth for a Bimac


Colossal Squid
Staff member
Moderator (Staff)
Nov 20, 2002
I am starting to think, maybe there's a problem with Lil Pumpkin. His rate of growth seems to have slowed considerably compared to Inklet. Inklet has doubled his size since he arrived. He is a non stop eating machine, as I remember of Ink and Hermin also. Lil P is still eating, but the growth is just not there. Nor is the personality. He was such a tiny baby when I got him. I am worried. The tank parameters are perfect. Temp is at 68, while Inklets is at 74. I am concerned at the lack of growth, being I've had him for 5 months. And as Inklet grows I can see a big difference between the two.

Any thoughts? Fraid I don't have a good feeling.

I don't know how useful this could be but he is definitely a bimac right? Are the temperatures in both tanks the same? Or could Lil P just be different?
Temperature is a factor in growth, and the bimac in the tank with the higher temperature will grow faster, according to what I've read and been told. I've talked with breeders who emphasized the importance of getting the octopuses to eat a lot when they are young - this can be a problem. I don't know what happens when they don't - maybe they just stay small. Certainly we had adult bimacs varying considerably in size among our first group of siblings. I really don't know all the ins and outs, but I'll try to find out more for you.

Personality differences in octopuses have been documented, so it's not unusual to have bimacs with entirely different personalities.

But this doesn't rule out some sort of problem for Lil Pumpkin - there is not much you can, just keep an eye on him and give him lots of good food, which I'm sure you're doing. Hope all turns out well.

Lower temps are supposed to prolong the lifespan - I don't know whether there's any real proof of this or whether a few degrees makes any difference. Very cold water octos seem to live longer than warm water octos.

Carol, can you estimate the size of Lil Pumpkin and Inklet?

Lil Pumpkin's mantle is the size of a large grape, maybe 1". Inklet's has to be probably 1 3/4" and his legs are thicker. Lil P's are thin. Curled up, Lil P is about the size of a quarter, while Inlet is bout the size of a 50 cent piece. When Inklet arrived, they were the same size. The growth rate of Inklet is amazing.

I'm not so sure the temp has anything to do with it. There's only a 4 degree difference.

I am wondering if there's such a thing as a birth defect where they just stop growing? His appetite is off also. :frown: I just tested the water, but I am going to do a water change tonight.

Hi Carol,

I was reading about a problem with human children called "failure to thrive", where they lose interest in eating and don't grow. Maybe Little P is "failing to thrive". This is treated in children by offering food and spending time with them holding a spoon with food in front of them until they eat. I don't know how that would translate to octopuses!

But octopuses do have different growth rates and some do get more food and grow more (I think Ollie was one of those - but I did notice that when she arrived, she had very sturdy legs, even though she wasn't very big. She seemed on her way to growing large.)

I'll try to find out more about octo growth for you.

corw314 said:
I am wondering if there's such a thing as a birth defect where they just stop growing? His appetite is off also. :frown: I just tested the water, but I am going to do a water change tonight.


Sounds like Pudge, he stayed small all his life too.
Was Pudge a Bimac? How long did you have him? I forget what happened with him.

As far as stress, nothing has changed in his location. I have had him for over 5 months. Maybe it is like Pudge.

Thanks Nancy! When I compare the growth rate to Ink and Hermin, it's just not there, at least not what I know of as normal.

I had Pudge for 4-5 months, he spent 3 months at the LFS and 3 before he was shipped to the LFS. He was a bimac and stopped eating in late December and died after my heater made the tank go from 68-72 degrees to about 85 in 8 hours. I never saw any significant growth in him either.
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