Sorry to hear about your fish. If you want I would be willing to send you 3-5 of them free you just pay shipping. Depending on where your located. Let me know. I feel your pain. Send me a pm. Incase I forget to check back with this topic.
Smell the tap water. Might be chlorene being flushed through your water lines to clean them. I had the same problem with my cichlids. Lost about 23 total.