HELPP

Question
Hi Karen, we have recently been given a 170litre tank and have in it
3 angels
4 mickey mouse
2 loaches
3 gouramis
2 silver dollars
1 shark

we have 2 filters the light is always kept on above tank. There is plenty of plastic plantation and hiding spots.
Today we realised our angels are missing there top fins and most of their tails and 2 of them are bleeding. This seems to have happened in one day. Also orange gourami is changing colour, he is going black across the top.

what is happening. Please help. We have looked on the internet and think it might be fin rot.
Thanks alot Gina

Answer
Hi Gina,
Its possible the angels may have been fin nipped severely by one or more of their tankmates. Its hard to pinpoint exactly who unless you observe who is charging at the angels. I would suspect (but not confirm) that the Silver dollars may have a part in it.

But I am also worried that toxins may be responsible for the fin damage and black mark across the gourami. Toxins like Ammonia are a major issue in fish tanks. Most aquariums are 'cycled' or have beneficial bacteria that take care of the ammonia issue by converting it into a  harmless chemical. But if this tank was torn down at all and set back up the bacteria colonies may have died out and then ammonia is allowed to spike.

You can easily test for ammonia yourself with a simple test kit from your petstore or you may also bring a sample of water to your petstore to have them test it. Although its best if you have your own test kit.

The beneficial bacteria are also called your 'biofilter' due to their job of 'filtering' your water of the toxins your fish produce from their waste. Regular aquarium filters cannot get rid of pollution in that form.

Just in case you aren't sure about it. The bacteria convert ammonia over in these steps-
*Bacteria establish to convert ammonia into  "Nitrite"
*Nitrite is still toxic
*Later, more bacteria develop to convert nitrite into "Nitrate"
*Nitrate is completely safe unless in extremely high amounts.

Again, like ammonia, you can test for all three levels-- ammonia, nitrite, nitrate with a simple test kit.

It is good to test your water a lot when your fish are acting sickly, because then you know what should be done or you can eliminate the possibility of polluted water which is the number 1 reason fish fall ill with bacterial and fungal infections, become highly susceptible to parasite infections and may simply die from the stress of it all.

Back to what you should do.

I would do a 30% water change just as a precaution. Always make sure the replacement water is equal in temp to your tank's (or just a little warmer) and make sure you always use water conditioner.

The next step would be getting your water tested so we can determine or rule out if the aquarium is cycled and the water is safe for them.

If it turns out there is ammonia or nitrites present. The aquarium needs to have time to cycle (most aquariums cycle in about 4-6 weeks).

The biofilter establishes on its own. But you'll need to make sure your new fish are able to make it through ok. You can do this by testing the water frequently and doing 30-50% water changes whenever the ammonia level gets too high. This wont hurt the biofilter. You can also use ammonia neutralizers and water conditioners that neutralize ammonia and nitrites like Amquel+ or Prime especially great when doing a water change.

Best of luck and I hope this helps!
let me know how the angels and gourami are doing...
Karen~