Dear all I have a 56l / 14 gallon tank. It's a 6 month old tank. Last month around 12 guppies died in a space of 1 week. The water parameters were perfect, I don't have the readings as I had my local pet shop check it for me, I had it checked on 2 different occasions in 2 different shops and none found any problem. Then this Sunday i bought 10 more guppies which all died within 4 days of purchasing them. I'm actually bewildered. Can anyone suggest what's going on. Note- the guppies were bought from a local breeder on the Internet and not from a pet shop. I live in Denmark and we have long days with just 4 hrs of darkness. Please help and ask questions which may be relevant to the situation. I also have some Platy fishes in my aquarium and also some Guppies more (bought from a pet shop) they seem to be doing fine.