Fish that likes to sit at the bottom of the tank!

Question
Hi Nicole,

I'm a little bit worried about a new goldfish I've recently got.  To give you background info on the tank, I've got a 125 litre tank with 3 goldfish, we do a 20-25% water change every other week, we have a strong filter and also an oxygen pump and several live plants.  We've had the water tested last week and all levels are fine.  We feed a variety of frozen bloodworms, dried daphnia and flakes to our fish, and they nibble the plants too.  We also put in a mushed-up pea about twice a week.  The tank has been up and running for about 6 months.  We originally had two fish but one recently died of what we suspect was swimbladder, so we got two new ones to keep the other guy company.  One of the new fish seems absolutely fine in general, but he spends a lot of time sitting at the bottom of the tank.  

Now as I've just lost a fish to swimbladder I'm really worried that this is the same thing, but he has no trouble swimming off the bottom of the tank when he wants to move, and he doesn't seem to sink at all in general, just when he wants to sit at the bottom.  Whenever we open the tank to give them food he has no trouble getting from the very bottom to the very top of the tank, and he has a good appetite.  The only other abnormal thing is that all three fish seem to have slightly redder gills than normal.

I'm a bit worried that I'm over-reacting, as he doesn't seem to have the same symptoms as the swimbladder fish (he's not stuck on his side - he's upright when he's at the bottom and when he's swimming, he's got a good appetite, he can swim around perfectly fine for hours) but I'm sure it's not normal for a goldfish to spend hours at a time just sat at the bottom of the tank!

Any advice or suggestions you can give will be greatfully received - I really don't want to lose another of my babies to swimbladder!

Thanks ever so much,
Laura (UK)

Answer
Good evening Laura,

Sorry to hear about your late goldfish. Are these fancy goldfish? Fancy goldfish are prone to lots of ailments that non-fancy goldfish are not so prone to. Basically, the selective breeding to produce those desirable traits such as the hunchbacked, compressed appearance of fancies means that they are not at as well equipped to do things like - swim! Their swim bladder is compromised due to their skeletal structure and their veil tails are prone to fin rot, their buggy eyes prone to popeye. The list goes on and on. Of course, I'm not sure what kind of goldfish you have.

In any case, the size of your tank is the bare minimum to house your three goldfish. Two goldfish really would have been better, but since you have the third, let's do what we can to make him well. First off, you are not changing nearly enough water. Change 50% of the water a week, goldfish breeders change 90% of their water weekly simply because these fish are so messy. I'm glad you have strong filtration, this is a must for goldfish. What I recommend is that you get one kind of filter that is rated for your sized tank, then you get another one rated for your sized tank. I prefer to combine canister filters with hang-on back power filters, this distributes the flow on both sides of the tank and keeps the water very clear. It also helps the oxygen exchange of the water by breaking the surface tension.

It wouldn't be a bad idea to rinse your filter media out twice a month. Use your tank's own water, so as not to harm the beneficial bacteria. I use a hose to siphon out the water then rinse my media under that hose. Use a combination of biological and mechanical media, chemical is optional. What that means is, use something such as ceramic hoops or pellets (such as Ehfisubstrat). Foam sponges provide both biological and mechanical filtration. Filter floss is very cheap and effective at removing particles, this is what mechanical filtration is all about. Carbon makes your water a little crisper and removes yellowing and odors, so it's fine to have, but not as important as the other two kinds of filtration. In fact, if you only have one filter unit filtering this tank, I would leave it out all together. I prefer to use Chemi-Pure (you can Google that) which lasts much longer than activated carbon and performs the same.

The most important thing is that you execute water changes. I hope you won't take offense, but when pet stores say your water is "fine" this means very little. Numbers are what counts, not opinions. My test kits say that 80 ppm of nitrates is safe and 100 ppm is acceptable! This isn't true, of course, nor is .5 of ammonia (which registers as "stress") safe, it is toxic! It's much better to have your own test kit, and see for yourself what your water tests for. If you only change water twice a month, I am nearly certain your nitrates are high. Strong filtration is definitely a plus, but nothing can offset the nitrogenous waste that goldfishes produce (especially in a relatively small volume of water) the way water changes can.

So change 50% of your water straightaway! You can add Epsom salts to the new water if you feel like your fish might have buoyancy problems. 1 teaspoon per 10 gallons (about 38 L) is fine. Do you use teaspoons in the UK? Sorry, I should know that! Google can convert most measurements for you. Just say "gallons to liters" and it will tell you what to multiply by. Also, you can add aquarium salt - which is really nothing but kosher or non-iodized cooking salt, so get it at the grocery store if you haven't already purchased it at the pet store. Add it at the same concentration as the Epsom salt. This will help your goldfish detoxify from any nitrite exposure. Try to feed vegetables as often as possible, and keep flakes and bloodworms to a minimum. I prefer to use pellets on goldfish since this keeps them from gulping air, also pellets are more stable in water than flakes. Soaking commercial foods beforehand is recommended by many goldfish keepers. Only feed as much as is consumed in 1-2 minutes.

I always recommend these two articles to goldfish keepers:
http://www.wetwebmedia.com/FWSubWebIndex/gldfshmalnut.htm
http://www.kokosgoldfish.com/food.html

Goldfish are omnivorous and will greedily devour most of anything, but their diet should include a lot of greens. So vegetables, plants (glad you make these available!) and Spirulina based commercial foods are healthiest for them. Goldfish would also do well on a paste food, such as the European Shrimp Mix that African cichlid keepers make for their fishes. You can Google those three words for recipes, if you're interested in making paste food for your goldies.

I hope that helps! See if a 50% water change perks up your goldfish. I do believe what you're experiencing is water quality related due to high nitrates. A light vacuuming of the surface might not hurt if you feel there might be uneaten food on the gravel bed. If the pH of your water is slipping downward (again, do test your water on a regular basis!) or is much lower than the pH of your tap water, you can be assured that there are organics, mostly from decaying food and feces, fouling your tank. A gravel vacuum and sizeable water change will make things right again.

Take care,
Nicole