What Am I Doing Wrong?

[Assaye]

OK guys, here's hoping for some good advice....

I've tested the water and the readings are: pH 7.8, Amonia 0ppm, Nitrite 0ppm and Nitrate 20-40ppm

The tank is a 30 litre BioOrb and I am down to one molly and one ghost catfish, they seem quite happy now, the water is clear and the sponge in the filter is quite new - I didn't know about leaving some in there when i changed the filter.

What should I do now? How many and what fish could I introduce - and when?!!

Thanks in advance

Hi Sue,

Your tests are looking good. You need to remember that by changing the sponge in the filter, you'll have thrown away a lot of the good bacteria so expect things to get grim again before they get better. In the BiOrb, you don't actually need to change the sponge very often at all - if ever - despite what the manufacturers guidelines say. Only change a bit of the sponge at a time (1/2-1/3) as you want to preserve as much bacteria as possible. Leave it a good couple of months (or longer) before you change the other 1/2-1/3, and so on.

Keep testing and keep up with those water changes!

As for new fish - wait until everything has been perfect for at least a week (ideally longer) in terms of water tests and make sure your fish are healthy and you've not had any deaths for a while, and then add a couple more fish.

In a tank as small as yours, you don't want any fish with an adult size that is over about 1.5-2 inches. Long term, you're only looking at about 7 small shoaling fish (like small tetras/rasboras) OR 4-5 mid-water fish (such as platies) OR 6-7 smaller mid-water fish (like guppies). It's a very small tank, unfortunately and getting interesting fish in there might take some research.

 

[sue barton]

Hi Sue,

Your tests are looking good. You need to remember that by changing the sponge in the filter, you'll have thrown away a lot of the good bacteria so expect things to get grim again before they get better. In the BiOrb, you don't actually need to change the sponge very often at all - if ever - despite what the manufacturers guidelines say. Only change a bit of the sponge at a time (1/2-1/3) as you want to preserve as much bacteria as possible. Leave it a good couple of months (or longer) before you change the other 1/2-1/3, and so on.

Keep testing and keep up with those water changes!

As for new fish - wait until everything has been perfect for at least a week (ideally longer) in terms of water tests and make sure your fish are healthy and you've not had any deaths for a while, and then add a couple more fish.

In a tank as small as yours, you don't want any fish with an adult size that is over about 1.5-2 inches. Long term, you're only looking at about 7 small shoaling fish (like small tetras/rasboras) OR 4-5 mid-water fish (such as platies) OR 6-7 smaller mid-water fish (like guppies). It's a very small tank, unfortunately and getting interesting fish in there might take some research.

Thank you Assaye

just a couple of questions...
Should I keep doing daily 50% water changes? I must confess that when the fish started to look better I've stopped doing the water changes so frequently, but what would you recommend with these test results? Does the Nitrate need to come down more? How often would you test the water to be sure it was stable?

I am a bit disappointed that I can't have more fish, but understand the reason now - and I certainly don't want to to carry on having deaths like I have recently! I think probably a few long tailed guppies will do for me
Would I need to introduce them one at a time?

Thanks for the advice, I wish I'd known all this earlier - but then, I probably would have been put off the whole thing - at least I know how nice it is to have them swimming around in the corner!

 

[Assaye]

Hi Sue,

Your tests are looking good. You need to remember that by changing the sponge in the filter, you'll have thrown away a lot of the good bacteria so expect things to get grim again before they get better. In the BiOrb, you don't actually need to change the sponge very often at all - if ever - despite what the manufacturers guidelines say. Only change a bit of the sponge at a time (1/2-1/3) as you want to preserve as much bacteria as possible. Leave it a good couple of months (or longer) before you change the other 1/2-1/3, and so on.

Keep testing and keep up with those water changes!

As for new fish - wait until everything has been perfect for at least a week (ideally longer) in terms of water tests and make sure your fish are healthy and you've not had any deaths for a while, and then add a couple more fish.

In a tank as small as yours, you don't want any fish with an adult size that is over about 1.5-2 inches. Long term, you're only looking at about 7 small shoaling fish (like small tetras/rasboras) OR 4-5 mid-water fish (such as platies) OR 6-7 smaller mid-water fish (like guppies). It's a very small tank, unfortunately and getting interesting fish in there might take some research.

Thank you Assaye

just a couple of questions...
Should I keep doing daily 50% water changes? I must confess that when the fish started to look better I've stopped doing the water changes so frequently, but what would you recommend with these test results? Does the Nitrate need to come down more? How often would you test the water to be sure it was stable?

I am a bit disappointed that I can't have more fish, but understand the reason now - and I certainly don't want to to carry on having deaths like I have recently! I think probably a few long tailed guppies will do for me
Would I need to introduce them one at a time?

Thanks for the advice, I wish I'd known all this earlier - but then, I probably would have been put off the whole thing - at least I know how nice it is to have them swimming around in the corner!

You said you had recently replaced the sponge in the filter - this could cause you to get bad readings again. Keep testing everyday for a week or so and do water changes if you need to.

An easy way to remember it is this - any time you change something in the tank (so replace the filter, add more fish, have a fish die, have sick fish, have a power cut, etc) test the water every day for a week. If the water is good for an entire week, you don't need to test again until you have a problem. If it is bad, keep testing and doing water changes until it is good again for a week.

Guppies would be perfect for your tank! Add them one or two at a time and remember to test your water. Be aware that your tiger bard could well bite their fins and you might be best rehoming him. With the cat and the molly, you're only going to want to have about 4 guppies. When the molly and catfish pass on (or you get them a bigger tank ) you could have more guppies.

The molly and glass cta do need a larger tank than 30 litres so if you don't rehome them, you need to give them plenty of space in your current tank.

Have you considered getting a cheap second hand tank (about 60-90 litres) and putting your molly and catfish in that? You could have some other fish in there as well and it'd mean you could have more guppies in the small tank and happier fish in the big tank! You could also do a fishless cycle on the larger tank and save yourself a lot of this worry, lol.