Strange Illness In Zebra Danios, Bst's, And Neons

[SkydiveSonic]

A little about my tank to start with -

45 gallon (US) (approx)
Fluval 3 filter (not the 3 plus) with foam inserts (not the floss kind)
Undergravel filter (no powerhead, just airstones)
1 live plant, several plastic
Temp at constant 25 degrees (77f)
6 neon tetras and 3 zebra danios living in there for about 2 months happily

The situation:
I added some healthy looking black skirt tetras (5 of them) to my tank a few days ago. The next day i noticed all the BST's were fine, although my neons had lost colour and weren't moving much. Like the zebras they had red gills. I left them overnight as my girlfriend told me to, and in the morning they were swimming around normally with no signs of illness. The weird thing is that evening, the same thing happened. The neons and zebras had red gills and loss of colour, and the skirts were fine. Again this morning they're all swimming around as if nothing had happened. All fish seem to be getting on ok - the skirts aren't being territorial etc - they swim with the neons etc quite happiliy.

Any ideas what's going on? it's stumped me.

 

[WILDER]

Need water stats in ammonia,nitrite,nitrate, and ph, as red gills can be due to poor water quality or gill flukes, also any signs of flicking and rubbing against objects or laboured breathing, if the neon tetra's went pale that is a sign of stress.

 

[SkydiveSonic]

I can't give those stats as i don't have any water testing kit. I do 20% water changes on a weekly basis and there's never been any problems before.

 

[WILDER]

I would get your water tested as soon as possilbe, and invest in some test kits of your own, plus tell them to write the reading down for you, i would do a water change, any increasing breathing or flicking and rubbing on objects.

With adding some new fish and not knowing water stats i will leave you this link to gill flukes.

http/www.fishdoc.co.uk/disease/flukes.htm

 

[SkydiveSonic]

Thanks for your help - sorry i couldn't give more data on the water. Appriciated

 

[Marcos]

I'm still a newbie but can reddened gills point to a lack of oxygen?

 

[WILDER]

If there was lack of 02 in the water the fish would be gasping at the surface of the tank, or breathing heavily.

 

[SkydiveSonic]

Trust me - there's not a lack of Oxygen in the tank. I've got 3 air stones in there, all with a nice amount of air coming out The fish are all fine now after the on-off-on-off illness. Has passed by itself. B)