Question about vitamin D3 as it affects prawn moult

[demonte1997]

First post on here but not new to aquarium trade or online forums.

I have a freshwater prawn that seems to be a M. Tenellum from Ecuador. His body is about 3.5" long and claws are considerably larger (7" long). He is housed in a 20-gallon long tank with a cave and some fake plants. I acquired him at the end of December when he was about 1" long. He's shed 4 times since. The shedding frequency was quite fast being a few days, then maybe a week and the last one being about 17 days. I've been waiting about 60 days for him to shed again and it doesn't appear that he's anywhere near doing it. There doesn't appear to be much information about this prawn on the web but what I have seen is that this prawn should get to be an upwards of 8" body length. Something seems off to me here.

I read that vitamin D3 alters moulting frequency. Please see http://www.thefishsite.com/articles/464 ... ater-prawn. "In M. rosenbergii addition of vitamin D3 interferes with the metabolism of calcium and inorganic phosphorus in the tissues, and alters moulting frequency." I assume most prawns mimic the giant blue prawns reaction to this vitamin.

Every pellet food I see for anything aquarium related has a D3 substitute in it. Right now, I'm feeding the prawn Sera Marin granules which are labeled for marine fish but seem to have the best ingredients and he loves them more than anything else.

Can anyone expound of the D3 thing or provide more info on this species prawn?

Thanks,

-Rick