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 How many Goldfish per Gallons?
KCMojo  [Life Member]
4/5/2009 8:31:26 PM
My wife is freaked. Our boys have 2 goldfish in a 5 Gallon tank.

Some "expert" on some sight says 1 Goldfish per 20 Gallons. I call BS on that but I don't know fish.

Anyone?
BillofRights  [Member]
4/5/2009 8:35:30 PM
One inch of fish per gallon is the generally accepted max. 2 goldfish in a 5 gallon tank will be OK as long as you change the water occasionally and don't overfeed them.

The fish would probably appreciate a filter or air stone, but I don't think it's strictly required for goldfish.
fastmover  [Team Member]
4/5/2009 8:37:08 PM
live or dead? the dead ones should stack better and fit tighter in a gallon container better i am thinking 75-100.
KCMojo  [Life Member]
4/5/2009 9:00:34 PM
Both great suggestions. She did not think so, But I did. TY
wild_Texas  [Member]
4/5/2009 9:12:48 PM
I know a local baitshop keeps them probably in a 50-100 per gallon ratio in the tanks
spd2230  [Member]
4/5/2009 9:31:53 PM
I allow 10-20 gallons per goldfish and have never had problems. Two goldfish in a 5 gal is too much fish if you want them to live. Goldfish are really dirty fish. The minimum size tank I would use for two small to medium fish is a 20 gal.
JD762  [Member]
4/5/2009 10:16:40 PM
To better answer your question we need to know what kind of goldfish. Carassius auratus, the "gold fish" is a domesticated animal and comes in many forms, like dogs for example. The needs for a Chihuahua are different then a great dane though technically they are the same animal, Canis lupus familiaris. The common "cheap" pr "feeder" goldfish are called comets and are better suited for outdoor ponds as the get 18+ inches. The other varieties are smaller but I wouldnt want to go with anything smaller then a 55 gallon for two. Excellent filtration and a good water change schedule of 50% bi weekly will ensure a long (sometimes up and over 50 years!) and healthy life.
K1rodeoboater  [Member]
4/5/2009 11:18:15 PM
here's what I tell people who I've installed ponds for

1" of fish for 1gal of water
KCMojo  [Life Member]
4/6/2009 1:36:04 AM
Originally Posted By JD762:
To better answer your question we need to know what kind of goldfish. Carassius auratus, the "gold fish" is a domesticated animal and comes in many forms, like dogs for example. The needs for a Chihuahua are different then a great dane though technically they are the same animal, Canis lupus familiaris. The common "cheap" pr "feeder" goldfish are called comets and are better suited for outdoor ponds as the get 18+ inches. The other varieties are smaller but I wouldnt want to go with anything smaller then a 55 gallon for two. Excellent filtration and a good water change schedule of 50% bi weekly will ensure a long (sometimes up and over 50 years!) and healthy life.


What Kind! Seriously. WALL MART GOLDFISH. And their will be a 2gal per flush toilet in their future before their will be a 55gal tank in their future for 2.

That like paying $600- for a Leapers scope.

Now I'm more interested in seeing these damn things at 100 yards. I can't have a dog in the house, but now I need 55gal tank for 2 WALL MART Goldfish. You are not helping.
Ductapeman  [Team Member]
4/6/2009 1:43:18 AM
Depends. How big is the cichlid? An Oscar will try to eat them all at once, while a Jack Dempsey will take his time . . .
ColonelHurtz  [Team Member]
4/6/2009 2:02:06 AM
Originally Posted By BillofRights:
One inch of fish per gallon is the generally accepted max. 2 goldfish in a 5 gallon tank will be OK as long as you change the water occasionally and don't overfeed them.

The fish would probably appreciate a filter or air stone, but I don't think it's strictly required for goldfish.


This is the rule in a filtered tank. Goldfish are considered "dirty" but two small ones in a 5gal tank should be ok.
Arms_Reach  [Team Member]
4/6/2009 3:41:38 AM
First you have to understand what biological forces are at play in your little box of water. I will just give you enough info to get a basic idea. Concider it "cliff notes".

This is the Nitrogen Cycle:

Ammonia/Ammonium NH3/NH4is mainly produced by fish waste and uneaten food. It is very toxic to fish, think burning alive.
In time an oxygen needing (aerobic) bacteria called nitrosomonas will literally fall out of the sky and start establishing itself in your aquarium.
Its whole purpose in life is to eat NH3/NH4 and it produces:


Nitrite NO2 which is almost as toxic as NH3/NH4 with regard to fish. Again, you will have an aerobic bacteria, this time called
nitrobactor come to live in your tank. It eats NO2 and produces:


Nitrate NO3: which is not all that bad for your goldfish. The main problem with NO3 is that it will build up in the water if you don't do water changes.
If NO3 builds up too much it will affect the nitrobactors ability to break down NO2 (toxic).


This whole process will take about a month (on average) to get from NH3/NH4 though NO2 and to NO3. Often times the bacteria nitrosomonas and nitrobactor
will be in "a free floating" form that will cause the water to become cloudy. This is not the main threat. The main threat is if the fish are being overcome by NH3/NH4
or NO2. There are test kits available to test these nitrogen compounds. They will cost more than your fish so you probably won't buy them. If the fish starts to act
listless you should change about 50% of the water. The white milky water will eventually calm down as the bacteria fixes itself to the surface areas of the aquarium
where it will live indefinitely until something changes its ability to survive, or until there is a spike in the level of nitrogen causing it to spawn and resulting in more
"free floating" bacteria.

This is what you need to know/remember/do:

-Do not over feed your fish. Their stomachs are smaller than one of their eye balls. You think you are making them happy giving them a lot of food. You are wrong. You will kill them. You are probably relizing right now that you have over fed the fish. Go change some of the water.

- Make sure your use a dechlorinator if your tap water has chlorine, or use bottled water. Not only will chlorine kill fish, it will kill bacteria.

- Change 50% of their water every week for the first month (about). After that period of time you can likely cut down to 20-30% once a month.

- Goldfish can tolerate a wide range of pH in the water as long as it remains somewhat steady. If you can manage to keep your pH below 7 (neutral), there will be less nitrogen available for ammonia and it will be converted to ammonium which is less toxic. Try not to let the pH go below 6.5.

- Your goldfish are omnivores however they have a considerably long intestinal track because of the amount of roughage they would naturally consume. Use goldfish food. Too much protein in their system could start too rot, leading to lots of problems other than more excessive nitrogen entering the water.


Good luck , you are attempting something that really requires more physical maintenance than some of the more reasonable 50-200 gallon
saltwater tanks I have had. The nitrogen levels in your tank can get out of whack much faster in 5 gallons verses 50 gallons. If your fish die,
take them out and flush them. Don't let their bodies decay and don't dump out the water and start over. Let the tank run for a while to finish
establishing the bacteria. Do a 20-30% water change and get more fish.

Obviously, I could talk for hours on this subject, and there are plenty of other things that can go wrong in an aquarium, but this is what will help
you the most as a beginner. We covered pH, NH3/NH4, NO2, and NO3. As far as chemistry goes, if you test and get a handle on those, you
could keep saltwater fish. The only additional thing to test for would be salinity. Now if you were asking about corals on the other hand, I could
write a book on husbandry, thats before we even start to talk about the different species and their needs....



Good luck , and the people at your local fish shop are probably trained to say 1" of fish per gallon. If you could show me any single body of water that has that going on....




edit for spelling
uglygun  [Member]
4/18/2009 8:10:41 PM
Originally Posted By KCMojo:
My wife is freaked. Our boys have 2 goldfish in a 5 Gallon tank.

Some "expert" on some sight says 1 Goldfish per 20 Gallons. I call BS on that but I don't know fish.

Anyone?




Freaking stupid. For every inch the fish is long, figure 1 gallon. Also depends on how hardy the fish are. If they are small gold fish, they will likely grow slowly due to ammonia/nitrates in the water. Only if they were big fish would it possibly be a problem. But hey, they are goldfish for crying out loud.

Somebody saying a tiny little gold fish needs 20 gallons per fish, they are likely closet animal rights activist sea kitten types.


Unless you are talking about a marine tank, I view fish as disposable decorations. Yeah, sucks when your bala shark grows from maybe 2 inches to 6+ inches but if he goes kapput I really don't care too much as it was a 2-3 dollar fish.

I've got a 55 gallon tank because it's the right size for my living room and is a part of the decor. I have a 140 gallons worth of filtration on that 55 gallon tank for if one day I decide to stock it beyond the typical rule(slowly per ammonia/nitrogen cycle logic). The tank has been cycled and is good to go but I'm not attached to the fish. Currently I have 3 small (1 1/2-3 inch) chiclid in the tank that are highly territorial so it's the only reason I'm at 3 fish in the tank right now. As they grow it's going to be entertaining to see how they fight for their space in the tank.