All My Fish Are Dying Help!

[LicianDragon]

I have a 20 gallon tropical community fish tank. In the past 24 hours I have lost 2 guppies, a male betta, a serpae tetra, a neon goby, and a peacock gudgeon. My ammonia and nitrite is zero, my nitrate is 5ppm. The temperature is 80F. Other fish in the tank are fancy guppies, red tiger platys, a golddust molly, 2 jullii cory cats, a weather loach, a halfbeak, and 2 african dwarf frogs.
None of the fish that have died showed any signs of being sick or injured, I would just come home and they'd be dead. I don't know what to do!!!! Help!!!

 

[This Old Spouse]

Even with your stats looking good, I'd still do a 90% water change, leaving enough water for them to swim upright.
 
I'd also lower the temp to about 76 or so.
 
You're way overstocked with fish that require different conditions and some that need to be in bigger shoals or bigger tanks.

 

[LicianDragon]

Even with your stats looking good, I'd still do a 90% water change, leaving enough water for them to swim upright.
 
I'd also lower the temp to about 76 or so.
 
You're way overstocked with fish that require different conditions and some that need to be in bigger shoals or bigger tanks.

I just did a 50% water changed yesterday. I've had these fish for more than 7 months now with no issues. The weather loach will need a bigger tank yes, but currently he's only 3 inches long. My tank is not overstocked by the inch of fish per gallon of water rule, plus I've never had issues with ammonia, nitrite, or nitrate.

 

[This Old Spouse]

You don't say how many guppies or platys you have, but you appear to be overstocked.
 
At any rate, obvious questions are did you use dechlorinator when you did the water change? Have you sprayed anything in the air near the tank? Used any cleaners near it?

 

[LicianDragon]

You don't say how many guppies or platys you have, but you appear to be overstocked.
 
At any rate, obvious questions are did you use dechlorinator when you did the water change? Have you sprayed anything in the air near the tank? Used any cleaners near it?

I currently have 2 guppies and 3 platies. Dechlorinator was used and I have not sprayed anything or used any cleaners near the tank.

 

[This Old Spouse]

What kind of substrate do you have?
 
With a conservative count, you have (had) 40" of fish in that 20g. Your stats might look good, but the stress of having all those fish in a small tank at a warm temp and insufficient shoals will certainly take its toll. I'm not saying that's what caused all the deaths, especially in 24 hours, but fish under stress can develop ailments that will shorten their lives.

 

[DerpPH]

yeah I agree with spouse... your stocking is quite wrong... your peacock gudgeon requires cooler temp then the others while neon gobies prefer faster current and need to migrate to saltwater when bigger.... just get your stocks right....

 

[PrairieSunflower]

Could you have used a contaminated container when adding fresh water to the tank?

 

[DerpPH]

Even with your stats looking good, I'd still do a 90% water change, leaving enough water for them to swim upright.
 
I'd also lower the temp to about 76 or so.
 
You're way overstocked with fish that require different conditions and some that need to be in bigger shoals or bigger tanks.

I just did a 50% water changed yesterday. I've had these fish for more than 7 months now with no issues. The weather loach will need a bigger tank yes, but currently he's only 3 inches long. My tank is not overstocked by the inch of fish per gallon of water rule, plus I've never had issues with ammonia, nitrite, or nitrate.

 oh and by the way dont follow the inch per gallon rule... it doesnt mean that you can keep a 10 inch goldfish in a 10 gallon tank dont it? follow their minimum or suggeste tank size... also get the stockings right... one of the most obvious reasons for this is your stocking...

 

[LicianDragon]

To answer This Old Spouse, I currently use eco-complete substrate since I have live plants.
To answer PrairieSunflower, I use a 3 gallon bucket for water changes that has only ever been used to handle aquarium water. There has never been anything else in it.
To answer DerpPH, I used the 1inch of fish rule for fish that have an adult size 4 inches and over, for any fish that will attain an adult size bigger than that, I do 2.5 gallons of water per inch of fish(so a 10 inch fish would have a 25 gal tank. This is only ever just an estimate, not a hard rule in my case.
All the research I did said my fish would be fine in the current water parameters and all schooling fish were kept in proper school numbers. 
 
I haven't lost any more fish and my water is still testing fine. None of the fish are showing signs of stress, though I never saw signs of stress in the fish that died either.

 

[Supraman]

I'd continue with water changes anyway as the water contains important minerals that both plant life and fish need to thrive. Also you could try aquarium salt ( not the salt for marine tanks ) . Your tank like stated before is quite overstocked and certain fish require bigger shoals. That's just what I can gather from this as I'm still learning myself.

 

[CoryLover95]

Alright...a few questions.

• How long has the tank been set up?
• Are you using a liquid test kit or test strips?
• How often do you do water changes?
• Did you cycle your tank before putting in the fish?  (obviously it is cycled by now, since you have 0 ammonia & nitrite, 5 nitrate)
• Do you have an airstone in the tank?  I ask this because it could possibly be a bizarre form of oxygen deprivation, but that's highly unlikely.

As mentioned before, you are overstocked.  Is it possible for you to return some fish to your LFS/give them to a friend with room in a tank?
I hope this all gets sorted out soon,
-CL95

 

[LicianDragon]

Alright...a few questions.

• How long has the tank been set up?
• Are you using a liquid test kit or test strips?
• How often do you do water changes?
• Did you cycle your tank before putting in the fish?  (obviously it is cycled by now, since you have 0 ammonia & nitrite, 5 nitrate)
• Do you have an airstone in the tank?  I ask this because it could possibly be a bizarre form of oxygen deprivation, but that's highly unlikely.

As mentioned before, you are overstocked.  Is it possible for you to return some fish to your LFS/give them to a friend with room in a tank?
I hope this all gets sorted out soon,
-CL95

The tank has been set up for 9 months. I use liquid test strips, I understand they're not as accurate as liquid but  I can do paper tests for free at work. I don't have the money for liquid tests unfortunately.
I change 6 gallons of water twice a week, having added aquarium salt since I set it up. Yes, I cycled the tank with 10 feeder guppies, of which 3 survived. Now I have guppy fry from them but the originals have since died.
I do not use an airstone, I have an aqueon filter for tanks up to 29 gal. I also have live plants in the tank. I returned the serpae tetras. So now my tank sits at
 
8 guppies( 1 is an adult female, the rest are fry all under 1/4 an inch long)<---I will be giving 5 of the guppies to a roommates turtle once they get a tiny bit bigger
3 tiger platies
3 julii cory cats
1 golddust molly
1 african dwarf frog
1 weather loach( he's currently just under 3 inches long, he will be moved to a bigger tank as he grows)
 
The wave of death seems to have stopped. I'm not sure what the initial cause was, I think the serpae tetras were harassing the guppies though that doesn't account for the death of my peacock gudgeon and neon goby, nor the death of 2 of the serpae's. I did another 60% water change today just to be safe. I won't be adding any more fish to my tank and the guppy fry will be turtle food once they get a bit bigger. Thanks very much for all your help guys! I always thought that as long as the ammonia, nitrite, and nitrate were fine in the tank, fish stock didn't matter as much. No more tetras for me!(not till I finally get that 125gal I've always wanted....) Thanks again!!

 

[LicianDragon]

Sorry, I meant to say that I'm using paper test strips to check my ammonia, nitrite, and nitrate levels. I can't afford the liquid tests right now.

 

[HayzH]

without the proper liquid test kits, you will not know your water parameters. I began with these test strips and they are completely useless. as they "bleed" into each other..
sorry for your losses btw x