Why are my brothers tetras dead

abcdefghijklmnopqrstuvwxy

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My brother has a 3.5 gallon with zebra danios, neon tetras, a betta, and ghost shrimp. Today all the neon tetras were dead but they had no sign of nipped fins from the betta. The tank has no heater and I tested the water and got 80 hardness and alkalinity, 7.3 PH, 10ppm nitrite, and 0ppm nitrate. I'm guessing it is either ammonia or temperature.
 
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abcdefghijklmnopqrstuvwxy

abcdefghijklmnopqrstuvwxy

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No ammonia test the tank is new

I had sponges in my 15 gallon and took a little bit out and put it in his tank to help is this good or bad
 

Donthemon

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Too many fish in too small of tank. Did it have a filter.? Nitrites should be 0. Is he aware of the nitrogen cycle?
 

Dunk2

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abcdefghijklmnopqrstuvwxy said:
No ammonia test the tank is new
Testing for ammonia is especially important in a new tank.

My guess would be too many fish in an uncycled tank is why fish are dying.
 

david1978

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Honestly only the betta is appropriate for that size tank and even that is debatable. 10 ppm of nitrite is toxic so without knowing what the ammonia reading is that alone will do it. Partial water changes to get the toxicity down is about the only way short term.
 

SM1199

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It's not really a "fix," but it can help, though only a little.

The underlying issue, as mentioned, is you have too many incompatible fish in too small of a tank, most of which are certainly not suitable for a 3.5 gallon tank. The only thing that can fix that is getting a larger tank or rehoming the fish.
 

Mongo75

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david1978 said:
Honestly only the betta is appropriate for that size tank and even that is debatable. 10 ppm of nitrite is toxic so without knowing what the ammonia reading is that alone will do it. Partial water changes to get the toxicity down is about the only way short term.
Are David and I the only ones that caught the 10 ppm nitrite. Like he said, that alone will kill your fish!
 

aoiumi

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That's way too many fish long-term for a 3.5 gal. It might work a week tops. Only the betta and the ghost shrimp would work, and even that would be very hard to care for.

If the nitrites are at 10 ppm then there's your answer. You'll probably want to do a 100% water change to get them down. Take all of the fish out, put them in a fish-safe tub with water, and change all the water in the tank. DO NOT SCRUB ANYTHING IN THE TANK. You're trying to grow good bacteria, so don't scrub it away, and don't change the filter media.

Use dechlorinator to remove chlorine and heavy metals. Chlorine will kill all that good bacteria you're working so hard for, along with your fish while it's at it.

The zebra danios aren't temp compatible with a betta fish. The tank is also too small for them, so if you want them over the betta you'll need a larger tank.

A heater isn't as important as clean water, and it's almost certainly the nitrites/ammonia that killed the tetras.

This can be saved but it will take some hard work and dedication. Fishkeeping isn't the easiest hobby, and it takes a lot of time to set up a tank that doesn't need much care. (Like 4 months lol)
 

SM1199

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Mongo75 said:
Are David and I the only ones that caught the 10 ppm nitrite. Like he said, that alone will kill your fish!
I caught it, I just thought it was assumed everyone saw that and understood. At this point it is more helpful to give recommendations to the OP to fix the problem than explain multiple times why they died - we all know why they died.
 

DuaneV

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As others have mentioned, anything over .5ppm (yes, that PIONT 5) is toxic. The higher the number goes, the more toxic it becomes.

You have way too many fish in way too small of a tank AND theyre not compatible. You need to upgrade to a bigger tank, rehome some fish, etc. A 3.5 is ONLY suitable for some shrimp, MAYBE a Betta, but I prefer a 5 gallon minimum for them. Neons need a school of 6 minimum and more than 10 gallons (a 20 gallon long and a bigger school is ideal). Theyre not temp compatible with a Betta either. You could keep a handful of Zebra Danios in a 10 gallon.

Change out 100% of the water now and figure out a plan to rehome/upgrade some tanks or your fish will continue to die.
 

kdwyer

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abcdefghijklmnopqrstuvwxy said:
My brother has a 3.5 gallon with zebra danios, neon tetras, a betta, and ghost shrimp. Today all the neon tetras were dead but they had no sign of nipped fins from the betta. The tank has no heater and I tested the water and got 80 hardness and alkalinity, 7.3 PH, 10ppm nitrite, and 0ppm nitrate. I'm guessing it is either ammonia or temperature.
tank is way too small. rule is 1 fish per one gallon.
 

DuaneV

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kdwyer said:
tank is way too small
Yes, it is.

kdwyer said:
rule is 1 fish per one gallon.
No, its not. Thats an archaic "rule" that isn't good to go by at all. WAY too many factors for it to work.
 

kdwyer

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DuaneV said:
Yes, it is.



No, its not. that's an archaic "rule" that isn't good to go by at all. WAY too many factors for it to work.
i agree i think fish need a lot more space. his tank is way too small for all of those fish.
 

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