Day 4 of the 5 day anti parasite treatment has been dosed and the ranchu appear to be bearing up OK. My new dosing method is meaning the water appears to be retaining the treatment dye colour better than previously. Let's hope this means it will prove more successful in eradicating the costia.
I've noticed some minor veining in the tail finnage of a couple of the ranchu, which i expect to be stress and/or water quality related. However, the fish are going into fresh (aged) water every day, so until the treatment course is over, there's very little i can do currently. In all other ways, the ranchu seem well. They have been constantly active and feeding.
The tubs I'm using are proving to be great. They each hold up to about 70 litres and included a lid, which is useful and helps to keep the water temperature stable during the night. I think they will also be great as hatching tubs for ranchu fry in their earliest days/weeks. They also only cost £8 each, which will be useful come spring time when i hope to be raising thousands of potential All Japan Ranchu Winners!