Tank is all brown and neon tetra glofish dead

[Jack13089]

Hello All,
Need some help!
I set up a 20 gallon tank and let it cycle for 6 weeks (pic of tank set up attached) Went and got 4 neon tertra and a catfish, they were thriving for a week and really e noted the way the tank looked. After the first week, I did a 30% water change, and bought 5 more neon tetras. After a day it’s like a plague hit my aquarium. Everyday this the fish kept dying, even the catfish died I am 6 days later and there is only 1 left. My tank is brown and there is brown algae everywhere. Let me also mention that the fishes tails looked tiny.
any idea what’s wrong or what I did wrong to prevent this from happening again? What should I do to get my tank rolling again??

 

[Seasoldier]

Hi, welcome to fishlore. Have you tested the tank's water parameters, if so what are they? pH, Ammonia, Nitrites & Nitrates? You said you'd bought neon tetras but the fish in the pic is not a neon. The tank looks very bare for fish to feel comfortable in, you need some tall structure or plants to break up sight lines or the fish will get stressed which opens them up to various illnesses. When you did the water change did you use a conditioner with the replacement water, something like Seachem Prime? Please don't think I'm criticising or getting at you, I'm not, we all make mistakes when starting out but if we're going to have a chance of helping you we need to know more.

 

[Lucyn]

The brown algae is just called diatom algae, completely natural, harmless, and very common in newly established aquariums since the cycle isn't very stable and the ecosystem is still working out its balance chemically.

When you have a freshly cycled tank, you need to add more fish VERY slowly or your cycle can crash which could have happened when you added in the new fish. Naturally, when you have more fish, you need to feed more to sustain all of them, thus increasing the overall bio-load overwhelming the aquarium's cycle. New fish are also susceptible to dying and when they die they create an insane amount of ammonia which can easily crash new cycles. Beneficial bacteria will take a long time to establish properly. The longer you wait to add more fish, the better. When I first started out, I wouldn't add fish to the aquarium for 4 weeks, but 2-3 weeks might be okay depending on factors like how much fish you're adding and already have.

The picture with the Tetra in the tank looks to also have ich or "white spot" disease, which also could have been the culprit. There's no way to know for sure if your cycle crashed for sure without testing for nitrite or Ammonia, but ich is a very slow killer, so I doubt it was just the ich. It was most likely brought in by the new fish you bought, which is why it's important to quarantine. Every new fish has a possibility of being sick and affecting your other healthy fish. By setting up a quarantine tank, you can isolate them and ensure they don't get your other aquatic friends sick.

The first thing I would do if you don't already have one is invest in a testing kit. This way you can know if your cycle is still active and go from there. I'm really sorry this happened, aquariums can be a lot of hard work and I know how discouraging it can be when stuff like this goes wrong, but you have plenty of time to learn for the future! Everyone in this hobby learns new things all the time no matter how long in the hobby. If you have any more questions, this forum is a great place to ask!

 

[Jack13089]

Hi, welcome to fishlore. Have you tested the tank's water parameters, if so what are they? pH, Ammonia, Nitrites & Nitrates? You said you'd bought neon tetras but the fish in the pic is not a neon. The tank looks very bare for fish to feel comfortable in, you need some tall structure or plants to break up sight lines or the fish will get stressed which opens them up to various illnesses. When you did the water change did you use a conditioner with the replacement water, something like Seachem Prime? Please don't think I'm criticising or getting at you, I'm not, we all make mistakes when starting out but if we're going to have a chance of helping you we need to know more.

Hey, all good! I did use a conditioner when doing the water change. The fish lost its color and likely going to die like the rest :-(. I was actually going to the fish store this weekend to buy some tall live plants.

The brown algae is just called diatom algae, completely natural, harmless, and very common in newly established aquariums since the cycle isn't very stable and the ecosystem is still working out its balance chemically.

When you have a freshly cycled tank, you need to add more fish VERY slowly or your cycle can crash which could have happened when you added in the new fish. Naturally, when you have more fish, you need to feed more to sustain all of them, thus increasing the overall bio-load overwhelming the aquarium's cycle. New fish are also susceptible to dying and when they die they create an insane amount of ammonia which can easily crash new cycles. Beneficial bacteria will take a long time to establish properly. The longer you wait to add more fish, the better. When I first started out, I wouldn't add fish to the aquarium for 4 weeks, but 2-3 weeks might be okay depending on factors like how much fish you're adding and already have.

The picture with the Tetra in the tank looks to also have ich or "white spot" disease, which also could have been the culprit. There's no way to know for sure if your cycle crashed for sure without testing for nitrite or Ammonia, but ich is a very slow killer, so I doubt it was just the ich. It was most likely brought in by the new fish you bought, which is why it's important to quarantine. Every new fish has a possibility of being sick and affecting your other healthy fish. By setting up a quarantine tank, you can isolate them and ensure they don't get your other aquatic friends sick.

The first thing I would do if you don't already have one is invest in a testing kit. This way you can know if your cycle is still active and go from there. I'm really sorry this happened, aquariums can be a lot of hard work and I know how discouraging it can be when stuff like this goes wrong, but you have plenty of time to learn for the future! Everyone in this hobby learns new things all the time no matter how long in the hobby. If you have any more questions, this forum is a great place to ask!

Thank you for this amazing response! I just ordered a testing kit so I can see what’s going on. The 2 last fish standing had the white spots on it so I am wondering if maybe there was a plague in my tank??
also, regarding adding too many fish to the tank. Is there a number or certain formula I should follow. I would like to have 10 neon tetras and a catfish in there.
should I clean the tank with new water or just leave it and let it cycle on it own for a few weeks before adding new fish?

 

[Lucyn]

Hey, all good! I did use a conditioner when doing the water change. The fish lost its color and likely going to die like the rest :-(. I was actually going to the fish store this weekend to buy some tall live plants.

Thank you for this amazing response! I just ordered a testing kit so I can see what’s going on. The 2 last fish standing had the white spots on it so I am wondering if maybe there was a plague in my tank??
also, regarding adding too many fish to the tank. Is there a number or certain formula I should follow. I would like to have 10 neon tetras and a catfish in there.
should I clean the tank with new water or just leave it and let it cycle on it own for a few weeks before adding new fish?

A lot of diseases are caused by not ideal parameters so it'd make sense if it was the parameters in collaboration with a disease like you mentioned. In terms of adding fish slowly, I wouldn't say there's a set formula because everyone's variables are so different, but the more gradual, the better. You can also do things like feed every 2-3 days and feed lightly and slowly, making sure they eat every piece you put in and nothing falls to the bottom to rot.

The fish will be more than fine temporarily eating every 48-72 hours while your cycle is still stabilizing. To give you a perspective, when fish get shipped from wholesalers, they aren't fed for 48-72 hours, get shipped in a bag for another 24-48 hours, and then the store doesn't feed them once they receive them for another 24 hours.

I'd start with 3-5 Tetra's, slowly feed more over a couple weeks, then the next couple weeks feed normally. After that, a month should have passed and you should be okay to get the 5 other Tetra's. To be safe, repeat the cycle of feeding lightly for a bit once you get the second batch of Tetra's. Something good to keep in mind is your bioload is only the amount of food you actually put in the tank. So if you got 10 Tetra's, but put the amount of food in you did with 5, then you'd have the same bioload.

I'd do exactly what you said and let your tank process the ammonia or nitrite if there is any. Once it's converted to nitrates, change the water and get fish as soon as you can because every day the tank doesn't have ammonia/nitrite to feed the cycle you will lose beneficial bacteria. If the tank only has nitrates, then that means your tank has already processed whatever there was and you're ready for fish OR there was never a crash and you'll be ready for fish after a water change. What I assumed was Ich should die off by the time you get new fish. If ich doesn't have a host for 48-72 hours, it'll die off.