I have a 70L divided between my male and female bettas. With the female i had 10 rummy nose tetras and with the male i had 10 neon tetras. They were all doing amazingly well until one day my female started swimming sideways. I had just bought a new filter and a heater, so i put them in because i thought she might've been cold. The next day, she was fine, but i found 3 dead rummy nose tetras over the next two days all i have left is the two bettas and three neons. Why could this have happened? my parents suggested it might've been the heater, but they were fine when i had my old heater in there. I also changed their food at the same time and we were worried that it might've been that. I think it might've been the filter. What do you guys think it might've been?
10 Rummynose Tetras, 10 Neon Tetras, 1 male Betta, 1 female Betta, correct? Did you add the 10 Rummynose and Neon Tetras on the same day? That might be the issue, adding 20 fish in one day will cause an ammonia spike and possibly kill the fish.
To be honest, that amount of fish in a 18 gallon tank is a bit too much. You also said you just bought a new filter? And I'm assuming you did not cycle your tank, so yeah I'll have to say overstocking led to an ammonia spike which resulted in the deaths.
Well maybe by getting the new filter, the cycle crashed since that's where the beneficial bacteria colonizes the most is in your filter media. With the cycle crashing maybe the ammonia spiked up?
That's what I could think of, that or a deadly disease just wiped them out completely. Something like this. . .
•Symptoms: Fish will start acting sick for no apparent reason. They could just die. Symptoms include weight loss, lethargy, open sores, deformities (scoliosis, bent spine), raised scales, fin and tail rot, gray lesions, and many others. Generally, if your fish are dying in large amounts everyday, it is probably TB. BEWARE HUMANS CAN CONTRACT TUBERCULOSIS FROM FISH, IT IS A POTENTIALLY DEADLY DISEASE.
•Treatment: There is no known cure, it will generally kill all fish that come in contact with it. It is highly contagious. Bleach does not kill it so throw away all supplies...
I grew up with "overstocked" fish tanks (57L full of tetras, plecos, gouramis, danios etc.) and fish survived in them for years. Back then we didn't have the internet to tell us how tanks should be stocked or about the bacterial cycling process. It seems your tank was balanced with just the right amount of bacteria to keep the ammonia low enough for the fish to survive. However, it's a tightrope balance and it doesn't take much to knock it out.
One thing could be the filter change. A lot of the bacteria that convert the ammonia to less harmful substances live in your filter. Not just the media but the tubing and inside of the filter itself. Replacing the filter could have taken away billions of beneficial bacteria, which caused an ammonia spike.
I doubt the new heater was the cause unless it was defective or improperly adjusted. I assume you were monitoring the temperature with the new heater and there were no temperature spikes. If the heater had shorted out, you'd have known about it (burns/possible fire).
Last thing I can think of is infection. One fish gets sick in a heavily stocked tank and it will spread literally within hours.
My advice would be to observe your surviving fish for a week or so. Assuming they are not sick, I'd say you don't have to scrub the tank out or disinfect it, in fact the bacteria in it would be beneficial and should be kept. 100% water change. Get a good water testing kit like API master freshwater and *use it regularly* from now on. A testing kit is an invaluable tool to tell you if you need an emergency water change due to poor quality.
Finally, I suggest you get a bigger tank if you want a community tank. Otherwise be prepared to change your water frequently or possibly lose more fish. IMO you could keep a nice betta sorority in the tank you have, and maybe get a small tank (around 20L?) for your male.
What was your reasoning to buy a new filter? As others have stated, by adding a new filter to a stocked tank you probabaly had an ammonia spike.
Never replace your filter medium unless it's falling apart. If it is clogged dip it in a bucket of old tank water and gently massage the outer surface with your hands to loosen up the gunk and drop it back inside the filter. Also don't run it under tap water as the chlorine will kill off the good bacteria.
I didnt have a filter before because i couldnt find one to suit the tank. It was really weird, all ten of my rummys died and 7 of my tetras, so i dont think it was a disease =S and it's not the food cause they're al doing fine now. maybe it was an ammonia spike =/ and when the others died there was less being produced... i'm thinking of adding 10 rummys again and a few shrimp, but no neons in with Tex (male) because they were usually hiding all the time anyways. i'm just afraid Caboose (female) will eat the shrimp because the lower part of the tank it kinda her domain. She didnt bother the rummy's, but do you think she'll eat the shrimp because they're smaller?
If you didn't have a filter your tank can't have been cycled and it's the reason your fish probably died. You would have needed a decent sized filter to give you the biological capacity to cope with your stocking.
Do you have an ammonia test kit? If not, I recommend buying at least that as you have no way of telling what your parameters are and with delicate species such as rummynose and neon tetras you really need to be on the ball with water quality. You can tell when your water quality is poor when your rummynose tetras lose the bright red colouration on their nose. Generally means something is not right.
Do not add anymore fish until you know what your parameters are and have correctly cycled your tank. For now do regular water changes to keep any ammonia down and I would give it 4-6 weeks before you even think of adding any new stock as it will take this long to cycle your tank.
Please do not buy more rummies. They are active fish and should have 30" of swimming room, which a divided 20 will not provide.
Once (and only once) we figure out what's wrong, I say look into better fish for 10 gallons of water. Posted via Mobile Device