Is My Little Minnow Sick?

[citrus-squid]

Hello all, I'm a little concerned about one of my White Cloud Mountain minnows. I went to get my first fish for my tank from Seapets a few weeks ago (tank was already cycled etc), I picked up 4 WCM minnows and 4 zebra danios for my 70L tank. I hadn't realised how unhealthy they were in the tank at Seapets (well, more like they weren't in best condition) until after a week in mine, the colours on both the minnows and the danios had become very intense and vibrant, and they started to swim with their fins nice and open. Unfortunately, one of the little minnows hasn't regained his colour. His fins are very washed out, red is very faded, the neon strip is dull, as is his whole body. He is very inactive, and seems to not have much of an appetite.

I was sure it wasn't the water chemistry as all the other fish are fine, but checked anyway and everything is fine, ammonia and nitrites both reading at 0, nitrates at around 5ppm. I'm at a loss as to why he's unwell, the 7 other fish are very active and very vibrant/healthy looking. Is there anything I can do for the little guy?

 

[citrus-squid]

Just an update - he seems to be getting better, he is much more mobile and this morning he actually ate some food. His colour is returning. I haven't done anything really. Does anyone have any ideas as to why he was unwell, and if I need to be concerned for the other minnows? I'm stumped.

 

[thereverendturtle]

Sounds like severe stress, which weakens their immune systems. His just took a little longer to get bad on track.

 

[citrus-squid]

Thank you Rev Turtle I was hoping it was just stress that he could recover from, and not the symptoms of something that I was being too stupid to notice. I decided to pick up 2 more minnows, which seems to have really triggered the shoaling behaviour in them, all of them look much happier for it. Also got some blood worms, which all the fish went crazy for and has livened them up. My little sickly minnow is now fit and healthy! What a relief