Just to get back to you on trying to identify what is male and female, thanks for your help to start with, this morning I was able to have a good proper look at them as three of were right at the front all grouped together. I noticed that two of the puffers had clear fin tails and one of the puffers had a very different yellowy fin tail. Now I dont know what this means, ill try and take a photo but of course will be hard to do so. Maybe one is just colouring up faster than the others...?I'm not sure, of the two new ones I got both were male but one had markings like my existing male and the other was spotty. I've had mine somewhere between 12-18 months. The male is a good inch at least(never tried to measure!) the female a bit smaller. The male is built like a tank, if anything around an inch could be described as such. I rehomed the 2 new males or you could have had one of them. A group of females is likely to be more tranquil tho.