One of my goldfish is very stressed and I'm not sure why

[sunev]

I (well, my daughter) have 2 goldfish, 4 months old. Everything's been fine, water changed regularly (20%, every 7-10 days), water conditioner and aquarium supplement added with each water change. Last week we realised that the sun was striking one corner of the tank and it had got quite a bit of algae (normally the blind is drawn). This is the first time we've had anything more than a very faint bit of algae on the side.

I've changed the water, more than usual, put in something that's supposed to break the algae down, have changed the filter so the water is being cleaned. Have checked nitrate levels, etc. using a all-in-one paper strip and all ok.

But although fish 1 (Daisy) is fine, fish 2 (Flappy) is sitting at the bottom of the tank looking very unhappy, tail pulled in quite tight and fins going a bit quick. Flappy's always been more nervous and gets stressed at water change whereas Daisy is no different.

What can I do?

Thanks!

Have to go and spend time with my children now, but wanted to add I know my tank is too small which is probably at least part of the problem. For 2 goldfish, what size should it be, what I can get away with upto what would be ideal? Again, thanks.

Hello :) Got your PM, not sure why this didn't come up on my active convos.

Anyway. Better sit down because 2 goldfish need a BIG tank. For a couple of fancy goldfish (the fat, round ones), I'd be looking at about 170-ish litres minimum. For a pair of regular goldfish, it'd be more like 200+ litres or ideally a pond- they are pond fish really, although they are fine in large enough tanks.

When you cleaned the filter, how did you clean it? What does the dip stick test for? Can you remember the exact levels? Are they eating and pooping OK?

Thanks. Any advice extremely welcome. dd keeps saying "they're only fish", but they've got character and I don't want them to suffer!

The filter is an i25. It has a cartridge which I replace approx. every 4 weeks - has carbon, zeolite (to remove ammonia) , floss (to remove debris). This got very grimy this time, because of the algae but is now running fine. Perhaps I should rinse it in the old water each time I clean the water as well? The dip stick tests for 6 things: chlorine, nitrate, nitrite, general hardness (GH), alkalinity (KH) and pH. These are all fine, but I wonder if it's very accurate so have ordered an API test kit.

They're eating and pooping extremely well, always have lots to clean away! They generally get fed once a day, sometimes twice, and come to the front of the tank when it's time. The happy fish sometimes chases the unhappy fish away.

Tank size is a bit scary, will have to think carefully about where it can go as I was told they shouldn't have daylight on them because of algae.

Thought goldfish were supposed to be an easy pet to keep!!

That actually sounds like a lot of stressy water changing to me, I don't do mine nearly as often. Maybe 1/4 once a month or less.

Do you add aquarium salt to the water? That's supposed to help with stress, I forget why.

No, you need to keep up with regular water changes, especially if the tank is too small. Normally you don't need carbon and zeolite, but since your tank isn't big enough then they will be helping with the filtration. They do need replacing quite often though. Do you know the volume of the tank?

Daylight isn't that bad, it's best to keep out of direct sunlight but algae only becomes a problem with excess nutrients like nitrAte and phosphate.

I would cut down to feeding once a day at the most and have one day a week when they are not fed. Goldfish do a very good impression of being hungry!

Aquarium salt is great for nitrIte poisoning and it won't do any harm to add any, but depending on the cause of the problem it might not fix it.

Goldfish used to be a lot tougher and I think people thought they were easy until they discovered that they should be living for 20 years and not 3. They are still easy to care for given the right conditions, but most people don't have the space.

The tank is tiny compared to what you're suggesting, only 20 litres and the fish have grown since we've got them. Will try the salt short-term and seriously look into getting a new tank in the next few days but it'll be a while before it's ready for them. Poor things.

Crikey, that is small. The sooner you can move them, the better. You can move the filter straight into the new tank so you won't have to wait until it's cycled.