Help Cory's dying☹️

[Fishnube88]

Got a some Cory's and nerite snails for my betta tank , everyone did great. But after seeing how cool they were I decided to buy the Cory's a bigger 29g tank and add 6 neon tetra. Brand new tank brand new clean water. (I know now I'm an idiot) I got it. Everyone good swimming happy. Within 4 hours all 6 tetras nose down in tank dead one by one. Then in 6 hours Julli Cory (my fav) barely swimming upsideways, 2 hrs later dead. 5 more hours Peppered Cory same thing. Snails fine. Got 4 red platys and baby Julli Cory today, seem fine zipping, eating... But worried what 12-24 hrs may bring. Any advice??? I almost feel like the new tank was so clean from the dirty tanks at the pet shop that the change shocked them....maybe totally wrong. Water parameters in order...don't know what is going on. Any help would be appreciated

 

[Kritastrophe]

How long was the new tank setup? Did you cycle the tank before adding your fish? What are your current readings for ammonia, nitrate, nitrite? What’s your ph and gh levels?

 

[Fishnube88]

How long was the new tank setup? Did you cycle the tank before adding your fish? What are your current readings for ammonia, nitrate, nitrite? What’s your ph and gh levels?

Ph was 7.1 N0.0 . I think the fatal mistake was not cycling the tank. To me unget a.pupoy u get puppy supplies, cat hampster etc. My bettas and goldfish never required much at all years ago but I've found recently theyre happier and healthier with more space/ filters etc..... They can live in bowls for years sadly..but the new aquarium on the same logic.i never thought about having to set if up so long before the fish. I think they didn't have enough good bacteria...something no one mentioned when I started out asking advice on the subjuecfmof a new freshwater tank. They just wanna sell

 

[Fishnube88]

Ph was 7.1 N0.0 . I think the fatal mistake was not cycling the tank. To me unget a.pupoy u get puppy supplies, cat hampster etc. My bettas and goldfish never required much at all years ago but I've found recently theyre happier and healthier with more space/ filters etc..... They can live in bowls for years sadly..but the new aquarium on the same logic.i never thought about having to set if up so long before the fish. I think they didn't have enough good bacteria...something no one mentioned when I started out asking advice on the subjuecfmof a new freshwater tank. They just wanna sell

They were perfect in the month old tank... But died in New water tank change yesterday. Did partial change tonight.with a starter ... Platys, baby cory doing great, neeite and mystery snails, nor betta affected by any of this. They are super. Different tank same water treatment

 

[Byron]

By "starter" I assume one of the bacterial supplements. This should work, but do not add more fish for several weeks and monitor the ammonia and nitrite and do a major water change if either are above zero.

Before other fish are added, you should sort out a few things. Primarily water parameters; these are hardness (GH) and pH primarily for your source (tap) water. Some fish need harder water, some softer, some manage in between so to speak.