unusual behaviour

Question
QUESTION: hello Chris, i have a 46L tank (NZ metric system) with 5 small coldwater fish (couple of shubunkins, a comet and a fantail), i dont have aafilter but i have an air pump and i put stress zyme and ammo lock in every week, i have finally cleared the water back to clear after treating my fish for white spot (which is all gone, and all the fish's dorsel fins are back up) one thing i have noticed tho is that the fish now spend all their time swimming up and around one top corner of the tank. they are not gasping for air, they eat well and they will move to eat but most of the time they just stay around that area. it is on the other side of the tank to the air pump (and the window) was just wondering whether or not this is something to be concerned about
(my partner thinks im being paranoid)
thanks in advance for your help

Aeronwy

ANSWER: Hi Aeronwy;

I'm not sure whether you mean they are near the air bubbles or opposite the air bubbles, but they need a filter for sure. They are all going to grow pretty large (15 cm at least) and can't survive long-term without a filter, epecially in such a small tank. There is oxygen from the bubbles but the waste they are making is staying in there with no place else to go. Shibunkins, fantails and comets are all types of goldfish that grow big and are very messy guys even while small. Each one needs 40 liters all to itself once he grows to be about 8 or 10 cm long. It would really help them to change 25% of their water every day until they get a filter....and shop for a larger tank as soon as you can. They will love you for it!

Here is a good web page about goldfish and their care;

http://www.firsttankguide.net/goldfish.php

Good luck and have fun!

At Your Service;
Chris Robbins

---------- FOLLOW-UP ----------

QUESTION: thanks Chris!

I have gone out and invested in a 120L tank and have bought a filter, just a quick qyestion- do filters also oxygenate the water or do i need an air pump aswell?

Answer
Hi Aeronwy;

That's great! They are going to just love their new tank!

The filter is usually adequate if the water flow breaks the surface of the water to allow gaseous exchange. I like bubbles in my tanks though. It helps the water stay more clear and can boost the oxygen level. The beneficial bacteria that keeps waste toxins under control needs oxygenated water too so the bubbles can help the whole system work more efficiently.

Have fun!

At Your Service;
Chris Robbins