How should I 'properly' clean out my fish?

[AtYourCervix]

Since morganna and morgeaus died the algae is building up and it needs a good scrub.

Now, normally I'd put out a bucket of water and leave for a couple of days, then put in fish, then clean out the tank, refill it with clean water, leave for a couple more days, then pop fishies back in.

I strongly suspect this is wrong though.

So how should I be doing it?

Hi there,

First of all, could you provide some details on the tank, such as the size, filtration type (if applicable) and the water conditions (pH, ammonia, nitrite and nitrate)?

Removing the fish during regular tank maintenance is not normally recommended with the exception for the very few occasions where you may have to strip down the tank whatever reason; such as moving the tank, aquascaping or due to a serious problem involving the tank, equipment or water conditions. It can also cause a fair amount of stress to the tank's inhabitants.

If you have a gravel siphon and two buckets, you can simply remove the water and built-up detritus from the tank using the siphon and replace the waste water with clean, dechlorinated water that's been pre-mixed in another bucket. The whole process shouldn't take longer than around 15-20 minutes, during which time the fish should remain in the tank.

It's also not advisable to replace more than 50% of the aquarium water in one go unless it's absolutely necessary, for example to lower harmful levels of ammonia or nitrite. Replacing most (>60-75%) or all of the water upsets the chemical and ecological balance in the aquarium. I recommend a weekly 10-25% water change regime, smaller but more frequent water changes are much more beneficial for the tank than one large water change every 2-4 weeks.

thanks. it's about 35l with 2 goldfish. i did have a couple of applesnails which ate the algae but they've recently died - hence the algae build up.

so i need a gravel syphon thing and something to scrape off the algae? maybe a couple more snails.

First of all, your tank is too small for one goldfish let alone two. I also wouldn't recommend an apple snail in a tank that small, depending on which type they can grow to 6"! Also, they aren't really coldwater snails, preferring water between 18 and 24 degrees.

Second, algae growth will either be down to too much light or too many nutrients. Goldfish are basically pooing machines so nutrients are going to be quite high in your tank. What sort of lights do you have?

Normal tank maintenance (I do this weekly), empty out 25% of water with a gravel syphon, use a sponge to clean off glass, gently squeeze out filter sponge in the water I've just syphoned. Replace water with dechlorinated water. I only replace filter sponges when they degrade and then only half at a time.

I'd only strip down the tank if I were doing some major replanting or when the tanks inhabitants came to the end of their lives and I was restarting it.

no lights on tank but it is in the kitchen which has huge windows so lots of natural light.
i do the part water change thing and rinse the sponge weekly.

so. things to do:

get bigger tank (although 35l was a guess and looking at it think it's bigger than that). get gravel syphon. move tank to somewhere with less light.

when I had fish I scrubbed the tank with a brush - pan brush for most of it, and toothbrush for the corners

Practical Fishkeeping article on goldfish requirements

I would recommend a minimum of 100l for a goldfish, then another 40l per goldfish - so you want a minimum of 140l really. All common goldfish can grow to up to 12", fancy goldfish up to 8", so please bear this in mind when looking for a tank. While it is true that goldfish are stunted by living in too small aquariums, this caused the internal organs to become misshapen, crushed and not work properly - leading to an early death.

Yes, having the tank in natural light will increase your algae growth but I think that your main problem is the large amount of waste 2 goldfish produce.