fin rot

One guppy has a streak of blood in his tail, three large slashes and discoloured (almost white) patches on his tail. The other guppy has a very ragged tail and is losing sections of it fast. I vacuumed the gravel as I always do when I clean the tank and did a large water change. I don't know...

Hi there. So, I decided after having my betta for 7 months that he needed some friends. First mistake. He was happy and healthy in a 10g tank with 2 assassin snails and a golden mystery snail. So, I add 6 neon tetras and 4 die within 2 days. I immediately pull the other 2 and put in a heated 1...