One guppy died.. how do I prevent more deaths?

[blueseas]

Okay I made a lot of mistakes in the recent week and i'm trying to figure out how to fix the problems and I thought other opinions could help. But simply, I put 2 Cory's (sterbai) and 4 guppy's in a 10 gallon tank. at the same time. I'm (now) aware of how awful that is. The tank was cycled before this but of course there was a huge ammonia spike and the fish started to develop red gills. Only after seeing this and researching, did i find out that Cory's need a tank bigger than 10 gallons and also need to be in a group of 4+ ! however i also learned that the red gills were a sign of major ammonia in the tank so i did a 45/50% water change and took some filter media from my other tank and put it into the guppy tank.

When I came home today one of my guppies had died and was lying on the bottom of the tank. I removed her and did another 30% water change (the last one i did was 3 days ago.) Of course I'm devastated and very annoyed that I made a mistake that resulted in the death of a fish, especially because that was so easily preventable if I had just researched more ! Anyway, i'm taking the Cory's back to the store and I'm going to keep the remaining 3 guppies (1 male, 2 females) if they survive. Are there any tips anybody could offer to keep the ammonia down in the tank except water changes?

here is my tank info:
10 gallons
26.c
Nitrate: 20mg/L
Nitrite: 0mg/L
pH: 6.8
KH: 40
GH: 60
The tank was cycling for 6 weeks before adding fish
I usually do 25% water changes every week

 

[FishGuest5123]

Be sure to remove any left over food after feeding and of course, any dead fish. Hope you don’t find any others. Returning the cories will help as an overstocked tank is an invitation for ammonia and nitrate spikes. Be sure to acclimate your fish to the tank before releasing them and always quarantine new stock. Guppies usually do well once acclimated and adjusted to tank. Be sure to test your water frequently for a few weeks and do water changes as needed. I do 50% weekly but have a larger tank with more fish. Good luck! Let us know if you need anything. Oh, one more thing... methylene blue is good to use if your fish are suffering from toxic amounts of ammonia, nitrites, or nitrates.

 

[Colin_T]

Your water test results don't have an ammonia reading.

If the tank was cycled for 6 weeks before you added fish, there should not have been an ammonia problem when you added fish. The cycling process allows filter bacteria to develop so when you do eventually add fish to the aquarium, there is plenty of beneficial filter bacteria available to keep the ammonia and nitrite levels at 0.

If you do get an ammonia or nitrite reading, or the fish appear to be suffering from something in the water, the best thing to do is a 75% water change and gravel clean the substrate. The big water change will dilute more nutrients from the water and leave less harmful stuff behind. Whereas if you do a 25% water change you remove 1/4 of the bad stuff but leave 3/4 behind. And if you do a 50% water change you remove half the bad stuff but leave half behind. A 75% water change removes 3/4 of the bad stuff and the remain 1/4 left behind is well diluted by the new water.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

If you have an ammonia or nitrite problem in the tank, reduce feeding to a couple of times a week and do a 75% water change and gravel clean the substrate 4-8 hours after feeding.

Make sure you only offer a small amount of food when you feed the fish. Crumble up 1 or 2 flakes and offer it to the fish. They should eat it all within 20-30 seconds. Any uneaten food should be syphoned out after a couple of minutes. It takes a bit of practice but you will get the hang of it pretty quickly.

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Your GH is 60. What is the measurement in (ppm, dGH, or something else)?
If the general hardness (GH) is only 60ppm (mg/l) then it is too soft for livebearers and does not have enough minerals in to maintain them in optimum health.

Livebearers (guppies platies, swordtails) need a GH around 200ppm and mollies need a GH of 250ppm.

If the water is soft (has 60ppm GH), you can buy mineral salts like a Rift Lake water conditioner to increase the GH. You can buy this from most pet shops or online and they will increase the GH, KH and pH. You would use them at about half dose.

You want to increase the calcium and magnesium chloride in the water and the Rift Lake water conditioners do this. They also add calcium and magnesium carbonate and bicarbonate to raise the KH and pH.