‘Crystal Red’ caridina shrimp: top-down view on the edge of the river
Bloody Mary shrimp (Neocaridina davidi) have been living in the Shrimphaus for a couple years now and are starting to get a little long in the tooth. Their solid dusky red colour also makes them difficult to see against the dark aquasoil and slate hardscape, although the new lighting has helped. I thought I’d pick up some more brightly coloured newcomers.
Caridina shrimp have interesting colours
Neocaridina come in interesting colours but with caridina shrimp there are more varieties and dramatic patterns. I was drawn to Crystal Red shrimp – with their solid white colouration and dramatic red stripe they definitely stand out against a dark background.
Caridina shrimp in hard water
Crystal Red shrimp are a type of Bee shrimp (Caridina cantonensis) that have been bred for their colouration. The near universal advice is: do not keep caridina shrimp in hard water. The origin story of caridina is that they derive from an acidic rainwater fed streams environment in Taiwan. Successful breeders keep caridina in water with almost no alkalinity, which of course also means low pH. There is still a requirement for some GH (calcium and magnesium) but this is also lower than for neocaridina shrimp. The Shrimphaus uses Cambridgeshire tap water which is both hard (high calcium and magnesium) and alkaline (high KH). Aware that Shrimphaus water is potentially problematic, I picked up a small handful of caridina shrimp from Best Aquarium Shrimps UK to have a test go. The shrimps arrived expertly packed, all alive and in great condition. I measured the KH of the water they arrived in and found it to be 0.8 dKH (15 ppm CaCO3) – in contrast the Shrimphaus measured in at 15 dKH (270 ppm CaCO3). We might have a problem here.
The first step was to drip acclimatise the caridina to the Shrimphaus water. I put a nice big piece of Christmas moss into the acclimatisation bowl and the shrimp seemed to appreciate that. The acclimatisation was uneventful and I released the caridina into the Shrimphaus proper with no evidence of obviously detrimental consequence. After 5 uneventful days in the Shrimphaus, I added in 10 more of them. There was one casualty straight away, and one more after a major water change, but other than that the new shrimp seem reasonably happy, feeding, swimming, exploring the plants and hardscape.
full view
caridina under plants
caridina closeup
Caridina won’t breed in hard water
I’m perfectly willing to believe the shrimp breeders that caridina will not breed in hard water (but we’ll see). The neocardina had one or two generations but then also seem to have stopped breeding. I think I’m ok with that. I have piles of fish in the Fireplace Aquarium and they don’t breed either. In some ways this is actually a desirable outcome really…
Only one left
Well crap. There were a few casualties that I found but the rest of the caridina just gradually disappeared, presumably they died and were eaten by their tank-mates (as shrimp will do). In an effort to keep the lone survivor going and maybe allow for a caridina retry, I have converted the Shrimphaus to a lower alkalinity setup. We’ll see how that goes.