Dr Mike Oxgreen
Member
A while ago I was having problems with my blue Neocaridina shrimp dying, and somebody in a fish shop told me that my temperature of 25°C was right at the top end of their range. As a result, I lowered my temperature to 23°C. Having read this interesting scientific study, I now believe that advice was wrong.
The study looked at the incubation and subsequent development of hatchlings at 24°C, 28°C and 32°C. It found some interesting results. In no particular order:
I'd really like to speed up my shrimps' reproduction, and in the light of the study it seems my lower temperature will be slowing down incubation significantly and may be reducing the survival rate of the babies. The study didn't address the effect of temperature on the fertility of adult females, but it's quite possible that a warmer temperature will bring females into breeding condition more frequently.
So I've decided I'm going to reverse my change of temperature and increase it initially to 24°C for a week, and if that seems okay I'll go up to 25°C. I won't go higher because it'll start affecting my plants.
For the avoidance of doubt, it's important to note that this applies to RCS (Neocaridina), but it does not apply to CRS (Caridina) which I believe do prefer rather cooler conditions.
The study looked at the incubation and subsequent development of hatchlings at 24°C, 28°C and 32°C. It found some interesting results. In no particular order:
- The incubation period is much longer at 24°C (21 days) than at 28°C (just 12 days).
- Growth rate of hatchlings at 24°C is slower for the first 30 days, but they then grow more quickly and actually catch up with their warmer colleagues such that after 90 days' growth they're the same size.
- Survival rate of hatchlings is better at 28°C than at 24°C.
- Hatchlings become sexually mature more quickly at 28°C than at 24°C, but at 32°C the young females fail to keep any eggs they produce.
- Contrary to what is sometimes written, the number of hatchlings produced by each female is not correlated with the size of the female.
I'd really like to speed up my shrimps' reproduction, and in the light of the study it seems my lower temperature will be slowing down incubation significantly and may be reducing the survival rate of the babies. The study didn't address the effect of temperature on the fertility of adult females, but it's quite possible that a warmer temperature will bring females into breeding condition more frequently.
So I've decided I'm going to reverse my change of temperature and increase it initially to 24°C for a week, and if that seems okay I'll go up to 25°C. I won't go higher because it'll start affecting my plants.
For the avoidance of doubt, it's important to note that this applies to RCS (Neocaridina), but it does not apply to CRS (Caridina) which I believe do prefer rather cooler conditions.