I confess, I have been a Bad Fish Owner

[TheSkiingGardener]

Please help me get my tank back on the straight and narrow.

It's a 60 litre tank I think, with a filter in a column with a coarse blue, fine blue and carbon filter.

It has plants growing in the gravel.

It has 2 goldfish and an algae eating black glass sucking fish that have lived there for a couple of years

It has black hair algae which has been getting a bit out of hand lately and is now growing on the gravel.

It has large stones in places.

I haven't changed the filters for a while.

I have a new bag of gravel and new filters of every sort.

Where do I start sorting this out? And what should I do first?

And then what should I do next?

Any advice very much appreciated.

Firstly, you shouldn't need to replace the gravel. Do you have a gravel cleaner? If not, I would suggest getting one and then do a large water change (about 30%), using the gravel cleaner to remove as much muck from the gravel as possible. It may help to remove the larger stones to clean under and behind.

How deep is the gravel? It may also help if you have more than a cm or 2 to remove some of it. Build up of detritus leaching phosphates and nitrates is one cause of algae and the deeper the gravel, the more stuff gets trapped.

Replace the carbon sponge and give your other filter sponges a good clean in some of the water you remove from the tank. You could possibly replace one of the other sponges but give it a good squidge with the old sponges first to make sure you transfer some filter bacteria. Don't replace all of the sponges at once, change one then leave it a few weeks before changing the other.

How long do you have the lights on for and is the tank next to a window? Reducing the amount of light the tank gets will also help to get rid of the algae. The plants should be fine with 8 hours of light.

Keep doing the water changes (25-30%) every week using the gravel cleaner and you should see an improvement.

Also, I hate to be the bearer of bad news but, a 60l tank isn't really suitable for goldfish longterm. They are greedy, messy fish that produce a lot of waste for their size and ultimately can reach 12" in length. They will eventually need either a 4 foot tank or a pond.

Hope this helps and I apologise if I sound patronising, I have a tendency to prattle on sometimes when it comes to fish :)

Thank you. Not at all patronising and extremely helpful advice!

The 2 goldfish we have now have been in there for about 4 years and are 3 inches long. They seem happy enough but I don't have an outside pond and a larger tank isn't a possibility. They are very messy though.

A fair bit of the gravel has the black hair algae on it so I thought replacing it would be helpful and will certainly improve the appearance short term I think while I deal with the underlying laziness lack of attention on my part.

Thanks again. I'll get cracking!