Need Help: Mystery deaths

[candicakes]

Hello everyone!

Long time aquarium lover, over 20 years of experience. I've owned several basic-moderate freshwater tanks and some aquatic turtles. I've never had super complicated setups, but I've dealt with live births, had a few tanks simultaneously, and was getting into the 100 gallon range. I had to give up my tanks during COVID and am just starting my first one since then, but I'm totally stumped.

I'm going small (office) 10 gallon, used tap water, water conditioner, stress coat+, have some live plants. Everything is brand new from the store. Normal setup- heater at 76* F, 20 gal Fluval filter, standard small bubbler, LED light. And some plastic decor alongside live plants. I've let that cycle for a few weeks.

I put in two Neon Tetra and two Dalmatian Molly's last night. Bought from PetSmart, no signs of illness, from 2 different tanks. Did a water test before hand, only some moderate hard water, to which I've been mixing in distilled water to lower the hardness. No nitrite, normal low-level nitrate, ph was slightly basic but normal ranges, alkalinity was ideal. Like I said, only hardness was high.

Acclimated 45 minutes in the bag in the tank, mixed in half water, waited 15 minutes. Then let them loose. The tetra's died within 4 hours. The first Molly died overnight. The other Molly is currently dying. I tried pulling it out and using pure distilled water at 75*F with a few drops of water conditioner and stress coat, but she looked worse in it.

I have no idea what happened. Any thoughts? I feel like I'm going crazy...

I'd love to save this one, but have no idea how. Please help!

 

[Andy Sager]

The speed of death sounds like a bad acclimation but before we can assume that, did you check the store's water parameters? If they were very different from yours, that too could have killed the fish that quickly. They were changed too rapidly. Also, Neons and Mollies are not a good combination. Neons need softer water while Mollies need harder water. If your water is hard and the mollies are dying, that also leans towards a bad acclimation.
Just for the record, you never use straight distilled water for fish. Fish need more than the H and the O in H2O. This is why you remineralize distilled water before adding to an aquarium.

A better acclimating method is to float the bag for 10-15 for temperature then IF the water parameters of your water match the parameters of the fish bag, pour the fish into a net over a container and then place them in the tank OR if you are unsure of the water parameters, open the bag of fish and place them in a bucket or container and add some of your tank water ( equal to 10% +/- of the volume of the water in the bag) to the container every 5-10 minutes until the water is 80-90% new water then net the fish and add them to the tank. You never want to add the water they came in( or now in the acclimation bucket) to your tank(s) as you don't know what pathogens may be in it from the store as well as the the ammonia level will most likely be high from the fish. If the container is small or there are a lot of fish in the acclimation container, you can add an air stone to it gently bubbling to help add oxygen to the water while they acclimate.
You should also know that most Box stores have a centralized system so just because they are in separate "tanks", they are really just in compartments of the same system with same water so you always want to ask the store if the fish you are getting are in the same water.
Hope this helps.

 

[Colin_T]

Hi and welcome to the forum

When fish die shortly after being added to an aquarium, it is usually poisoning or a massive change in water chemistry that causes the fish to go into shock (normally poisoning tho).

Did you use any cleaning products when cleaning the ornaments, tank, filter, gravel, etc?
Do you have anything on your hands that might wash off in water (moisturising cream, soap residue, hand sanitiser, etc)?
Do you have clean buckets and hoses specifically for the fish tanks?

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What is the GH (general hardness), KH (carbonate hardness) and pH of your water supply (in numbers)?
This information can usually be obtained from your water supply company's website (Water Analysis Report) or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg: ppm, dGH, or something else).

Depending on what the GH of your water is, will determine what fish you should keep.

Angelfish, discus, most tetras, most barbs, Bettas, gouramis, rasbora, Corydoras and small species of suckermouth catfish all occur in soft water (GH below 150ppm) and a pH below 7.0.

Livebearers (guppies, platies, swordtails, mollies), rainbowfish and goldfish occur in medium hard water with a GH around 200-250ppm and a pH above 7.0.

If you have very hard water (GH above 300ppm) then look at African Rift Lake cichlids, or use distilled or reverse osmosis water to reduce the GH and keep fishes from softer water.

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Your tank is probably too small for mollies, swordtails and platies. Mollies also need hard water otherwise they don't do well.

Do not buy balloon mollies or any balloon fish because these fish suffer from internal issues and usually have shorter lives due to having their bodies shortened.

Neon tetras should be kept in groups of 10 or more. However, due to the current issue, I would suggest flushing the tank out and refilling with clean tap water. Add some dechlorinator and let it run for a week (preferably with live plants in). Then add a couple of neons (assuming the GH is suitable). See how they go over a week and if they are fine, then get 8 more neons to make the group.

 

[bigchris87]

I found with myself if acclimatising in bag my death rate was much higher did you.open the bag when acclimatising or leave the bag sealed I always drip acclimatise in to an open container now over 1hr period an had no deaths since due to this issue