Fish Tank Weirdness

Aegis

My sister's had a fish tank for several years now (just a 10 gallon one for smaller fish) without very much trouble (though at times without many fish). Recently she purchased 3 small-round fish (I have no clue what they are) and a pair of sharks, as well as clean the tank, all the filters, the rocks, fixtures, etc, change the water entirely, and generally just follow all the standard fish-tank maintenance advice her and my father got. Since then, the water itself has rather rapidly (within a week or two) turned yellowish and murky, with sediment that appears brownish "gunk" all throughout the tank, on the rocks, plastic plants, everything. There is also a rather unpleasant fishy odour now coming from the tank, and 3 fish (one of the round ones, one shark, and one fish that was already 3 years old there that we always had) have already bit the bucket with the prospects for the remaining ones not that terribly good, and we just have no idea what's causing this since the tank was never this bad before cleaning it.

Any help would be appreciated, thanks!

Edit: Make that 4 fish dying, just walked upstairs now and noticed one of the round ones floating upside down at the top

JHunz

You should get a tester kit and check the mineral levels and such. It might be the water you're putting in.

Nova_C

Also, what kind of sharks? It may not matter, but I've never heard of any kind of fish that is given the name shark that can live in a 10 gallon. Are the small round fish discus? If so, they are WAY too big for a 10. It sounds like your sister's tank is heavily overstocked.

Can you find out what the actual species are? That's important.

Aegis

JHunz wrote: »

You should get a tester kit and check the mineral levels and such. It might be the water you're putting in.

Yea, parents decided to pick today to go to pet store and ask about what's wrong with fish tank and according to them its probably the water. Developers just on street above us have been digging not just for homes (brand new subdivision where our house is) but for a new school, and doing water work, so store lady figures it is probably something in the water when we cleaned it leading to an algae bloom.

Also, parents/sister have no idea what species the sharks or the other fish are (first time she's gotten sharks, just 3-4 weeks ago), but they are about 2 inches long. I'll see if I can dig up the species name somewhere.

Diomedes240z

You shouldn't rip through the whole tank like that when you clean it. It's not the filter itself that cleans the water, but the bacteria that inhabits it. Right now, your tank is probably full of ammonia (and maybe some nitrite) because you don't have the bacteria to break it down into less toxic forms of waste. When you clean a fish tank, never change more than 1/2 of the water, and never replace all the filter medium in one hit.

It will take two weeks to a month for the bacteria to develop. Until then, you might have to change 1/3 of the water every two days or so to keep the unbroken down waste levels down.

JHunz

Also, if you don't have any algae-eaters you should probably get one. Put a couple snails in the tank, or one of those stupid fish that sticks its mouth on the walls and looks dumb.

supabeast

Aegis is right, that thorough tank cleaning probably killed every useful bacterium in the tank. Upsetting the balance of small fishtank just a little is the best way to kill off everything inside, replacing all of the water was absolutely the stupidest thing that your sister could have done. Any fish left will probably die. Once they’re dead, change the water again and then go to the pet store and buy small aquatic plant. Let the tank run with only the plant in there for at least a week; the bacteria that came in on the plant will breed in the tank and then you can start adding fish, one at a time, no more than one a week.

Also, don’t try putting so many fish in such a tiny tank. I would never push a tank that small past three small fish.

tech_hunter

The general rule is about half a gallon of water for each inch of fish. As other have said emptying all the water was a bad idea because all the helpful bacteria are dead. Also the work on your water system thats being done could have atributed but I think it was mostly due to the full cleaning that was done. First thing is get a testing kit usually they sell 2 kinds saltwater and freshwater, the only difference is the saltwater usually tests for a few more things than the freshwater so either will do. After that to get the tank back to normal you will need to remove 1/3 of the water every 2 days and I would recomend replaceing that water with spring or filtered water from a grocery store. Getting an algae eater is a good idea for later but its not going to help much with a full out algal bloom.

Feral

So much good advice given in this thread so far. I agree that you're overcleaning.

Seriously, though, your tank is too small. I guarantee it. Without knowing what kind of sharks you got, it's difficult to know how big a tank you need, but it's definitely going to be several times larger than 10 gallons.

tech_hunter's guideline of 1/2 gallon per inch of fish is actually too small by half; the usual rule is 1 gallon per inch, but that's highly dependent upon the type of fish. Most sharks, being predatory and territorial, need even more space than that.

Jimmy King

I can't give any more advice about the tank/cleaning/etc than has already been given, but I can suggest the most likely shark. More than likely they were Bala Sharks. They are pretty common in pet stores that sell fish, fairly small (when you purchase them), and relatively inexpensive. I'm not sure how big they get, all that I've seen have been roughly the same size as goldfish are when you buy them, but the recommended tank sizes in that wikipedia entry suggest that they might get quite a bit bigger and 10 gallons is WAY too small for even one, let alone multiple Bala sharks and a few other fish.

Nova_C

Bala sharks grow to over a foot in length and are very fast and active swimmers (Incidentally, they're a kind of minnow :P). They needs lots of room to swim and are shoaling fish, so they should be in a school of at least three or four, six is preferable. What that means is, if they are indeed Balas, then you need 100+ gallons to properly house them.

The inch of fish per gallon rule is basically bunk, however. Every kind of fish is different. If the fish don't grow any larger than an inch (IE, some tetras) maybe you can get away with that, but throw that out. The best thing to do is research each species of fish you want individually BEFORE you buy them, find out their maximum size and how territorial/aggressive they are and plan your stock that way.

Algae eaters are great, but there are so many different kinds. I don't know of any Plecostomus (Pleco as they're commonly called - many species, but the most common is the 'common pleco', which grows to over 2 feet in length) that will fit in a 10 gallon, but a couple of Otocinculus (Otos) would work. I have 3 in my 55 gallon and they don't get rid of all the algae, but they make it a lot easier to keep up with it (I have a planted tank). They also stay small and have a small bio load.

drinkinstout

okay yeah, deep cleaning everything and then putting in way too many fish at once (and total) is what went wrong.

Most of the advice here is sound and I offer you some links: The Nitrogen Cycle in a nutshell, Aquarium Advice forums <-- a very good resource for fishy needs

Aegis

Yea, parents are taking advice and looking at not repeating mistake of emptying everything in one go, and I think picking up what was suggested here to clean up with algae. And while that one picture of a bala shark doesn't quite look exactly like the one we have this one,

http://www.bbayaquariums.com/select-action.cfm?ID=25

Does -.- Which makes me worried. Thanks though with all the cleaning and general maintenance advice, tis been a help.

Nova_C

Well, then you have bala sharks and I recommend you return them straight away. They're going to get stunted really quickly in a 10 gallon, which means they'll live shortened life spans, suffer organ problems/failure and be prone to infection.