My question is concerning exactly what you are supposed to do to maintain a healthy aquarium. I've heard some sources say it's ok to do a water change once a month, and some say once a week. Some say 30%, some say 50%. Also, is it a good idea to add salt and bacteria supplement to the aquarium on a regular basis? I have been adding it to mine because I was under the impression that it helped the fish's electrolytes or stress levels or something....now after looking around here a little I am not sure that is good for the fish. Also, I have been doing about a 30% water change every couple of weeks.

The number of waterchanges you need to do may vary and even change for each tank you own. You need to test your water parameters to determine how often and how much water to change. Once a tank is fully cycled, which means you have some nitrATES, and zero ammonia and nitrITES, you should not need to add any supplemental bacteria. With a cycled tank you want to keep the nitrates at as low of a number as possible. Below 20ppm is best, but some fish can tolerate up to 40ppm for short periods without apparent ill effects. You should never let the nitrates get above 40 ppm.

I have multiple tanks, each a different size and stocked differently. One tank I change the water to replenish the electrolytes, but the nirtates have never gotten above 5ppm ever. Another tank I have I need to do either two 50% changes a week, or one 75% change to keep the nitrates at a safe level. In general with goldfish if you are stocked to one fancy per 10 gallons, or 1 common/commet per 20 gallons, you will probably need to do at least a 50% change every week to keep the water healthy for your fish.

Adding salt is something of a personal choice, some people keep their tanks salted at a very low level all the time, others do not salt at all after the quarantine period is over. I personally do not salt my goldfish tanks because they do just fine without it. Sometimes if you keep a tank salted at low levels certain parasites can gain an immunity to the salt, and if you got an outbreak it may make treating for it harder.

Hope this helps.

Great advice Liz

Acidstars9, if you tell us about your tank we can help you figure out what you need to be doing. How big is it? How many fish? What kind of filter? Etc. The more details the better.

I have a 50 gallon aquarium with 5 different types of goldfish, a plecostomus, and some tetras. I have some live plants in there, I usually do around a 30% water change every couple of weeks. I have a Penguin 350 filter with 2 bio-wheels, ceramic rings and foam pads on each side.

hello acidstars~

first off, welcome to koko's!!!
you'll find that everyone here at koko's is eager to help and you might get the same information from members repeatedly, but we just want to help you out and give your fish babies the best possible environment. (it can be overwhelming at times).

okay, so... down to the business at hand...

the rule of thumb for goldfish is:
10 gal per fancy (double tail) goldfish
20 gal per common/comet (single tail) goldfish

so depending on your 5 goldfish, your tank is just the right size if they were the only fish in there.

you also want to have 10 times the filtration as the tank size...
so for instance since your tank is 50 gallons, you'd want 50 x 10 which is 500 gallons per hour on your filter.
your penguin 350, while it has great biological filtration only runs at i believe 350 gph... so you want to find another 150 gph or more.
it never hurts to over filter your tank especially since yours is a little bit overstocked.

~~~~~~~~~~~~~~
your pleco... do you happen to know what kind of pleco you've got? some species of plecos will become aggressive as they get older and may begin to harass your goldfish.

~~~~~~~~~~~~~~
as for the tetras...
tetras are tropical fish and require different temperatures as goldfish. it's not ideal to house these fish together not only because of the temperature differences, but once your goldfish get bigger, they may find the tetras to be tasty morsels during "snack time". the two types of fish also have different dietary needs.

~~~~~~~~~~~~~~
as for water changes, that all comes down to whether or not the tank is overstocked and water parameters. if you don't have a freshwater aquarium test kit, it's a good idea to look into getting one. the test drop kind are the best and many of the members here at koko's use Aquarium Pharmaceuticals.

please be sure to ask if you've got any other specific questions!
we're glad to have you here and hope to see you around the forum lots!

It really surprises me that on here it says you are supposed to have a 500 gallon/hour filter on a 50 gallon tank...when I went out shopping for a filter I wanted to make sure I got the right one. So I looked around and the one I got is marked as being ok for even more than a 50 gallon. Other filters seem to also be marked wrong. I think I am either going to get a new internal filter to go along with the one I already have, or just set up an old one that I have. With the one I already have and one more, it should be more than enough.

I've been trying to figure out the type of pleco I have but it's difficult because there are so many. Next time I go to the pet store I will stop by the plecos and see what kind they are.

The tetras were my boyfriend's idea as just a little addition to the tank. Honestly, the health of the goldfish is more important to me than they are.

I have been testing the water and everything is good except the nitrates could be lower. I was thinking maybe I should start doing like a 50% water change instead of a 30% and see if that helps?

oh... about the filtration.

not all fish require 10x filtration,
and it is just very highly recommended for goldfish because they are such messy little (or big, chubby, poo producing) critters.

so it's very well possible that the filter you have would work just fine on your 50 gal tank for tropical fish, but for goldfish more filtration is always better.

the nice thing though is it's combined filtration so it's not just one filter that has to run 500 gph... you could have two 250's or three or four filters on one tank. the more filtration on an goldie tank, the better.

::edit::

also, don't worry about performing large water changes...

lots of times i think people are afraid to do large water changes,
but my typical water change on my 72 gal is about 65-75% at a time.

I added one of my old filters that I had to my 50 gallon, so now combined it is filtering 500 gallons per hour. For some reason I remember a long time ago someone telling me never to change more than a certain % of the water...but from what people are saying on here, it seems like that just isn't true.

yep you could do 100% waterchange ..all the benefical bacteria that breaks down waste is in the filter on the biomedia like filterpads ,floss biosponge ..or whatever else you use that is what you don't want to touch ecspecially in a cycling tank the more filters the more filtration plus more room for benefical bacteria

haha yes that's one of the first things i learned here.
i think for the most part, we're taught to leave a percentage of the "old" water in so that we don't lose the bacteria,
but if there's decorations, gravel, and a filter on the tank, then there's plenty of bacteria living in the nooks and crannies to keep the cycle.

it is however a bad idea to clean everything out like a 100% water change and cleaning out all the filters, etc.
i usually reserve 100% water changes for extreme measures when there is no other choice.

also, the amount changed is a judgement call based on the water parameters.
so everything's kinda tied in together.