goldfish stress

Question
Hello, i acquired a couple of goldfish from an old lady, they are in  60l tank. The tank was filthy when i got it so i took the fish out in some of their water, cleaned the tank, filter and plants, then refilled the tank, left for a day then added the fish in a jug with some of the old water. I left some of the ornaments out as they were too dirty! For the first day or two the fish were behaving normally, now I'm worried that they are showing signs of stress, i caught one 'pecking' at the other one and chasing him around, they always 'play' with each other but papa seems to be bullying Nana now! They both always seem to be searching for food and drink a whole lot of water at the surface very frequently sometimes making gulping noises. Papa has started to do this weird fast swimming thing as well floating to the top then quickly swimming down. Does this all sound normal, im worried that they may be stressed or underfed (they get a small pinch of flake food every morning). Thanks

Answer
Hi Letitia,

You'll be happy to know that most of that behavior is normal. It is close to natural Goldfish breeding season right now, and assuming that you have one male and one female, they are probably trying to mate. Goldfish always search for food. Don't overfeed them - it's one of the most common mistakes. Goldfish don't die from the overfeeding itself - but rather the decomposing wasted extra food that turns into ammonia and other toxins which poison fish. A pinch every morning is perfect! If you want to encourage some brighter colors, or general health improvement, feeding a variety of freeze-dried/frozen foods is great in addition to your basic flakes. Frozen or freeze-dried foods will be available at your local fish store.

Are your Goldfish constantly at the surface, like they need air? If so, your tank might not have enough oxygen. Adding an air pump and an airstone will help improve oxygen levels. It's the surface agitation created by the popping bubbles that actually introduces oxygen, rather than the air pumped into the tank, so positioning your filter so that the water output breaks the surface of the water will also help.

I hope this helps, Good luck and Happy Fishkeeping!