Very sad day today.

[Lajos_Detari]

In my opinion, electrocution rarely kill fish.
Electricity flow from high to low voltage point.
It occurs mainly in human who touched a high voltage source and is standing bare footed on the floor(low voltage) at the same time.
So, if there is high voltage on the tank or water, the person will get electrocuted when he touched the tank or water while standing bare footed without any rubber(insulated) shoes.
But the fish most likely won't be affected since the whole water is at the same voltage level.

Anyway, here are some common reasons for fast fish death:

1.6. Aquarium Fast Fish Deaths - Aquarium Science

There are some things which kill lots of fish rapidly with no symptoms: If the fish died just after a water change: With chlorinated water and a large water change, a chlorine pulse can be to blame (VERY common). With well water and a large water change, low oxygen and/or high carbon dioxide can be

aquariumscience.org

 

[Lynnzer]

In my opinion, electrocution rarely kill fish.
Electricity flow from high to low voltage point.
It occurs mainly in human who touched a high voltage source and is standing bare footed on the floor(low voltage) at the same time.

Anyway, here are some common reasons for fast fish death:

1.6. Aquarium Fast Fish Deaths - Aquarium Science

There are some things which kill lots of fish rapidly with no symptoms: If the fish died just after a water change: With chlorinated water and a large water change, a chlorine pulse can be to blame (VERY common). With well water and a large water change, low oxygen and/or high carbon dioxide can be

aquariumscience.org

That's why birds don't get electrocuted when they land on overhead lines

 

[Essjay]

API has a dechlorinator that is nothing but dechlorinator. My local stores don't carry it as consumers want the aloe stuff.

That's the one I use. The only shop I know stocks isn't very local so I get mine from eBay.


It's API Tap Water Conditioner which contains only something to remove chlorine and something to bind metals.
It does not contain anything to detoxify ammonia.
It does not contain anything to "promote the slime coat".
It does not contain anything to "calm fish".


So far it's the only water conditioner I've found which does not contain at least one of the last three.

 

[Naughts]

@Boromir stated they did a water change with conditioner last week (post #3) and the fish died overnight Sunday/Monday (post #1) so I don't think it is likely to have been caused by the water change/conditioner.

 

[Deleted member 149562]

@Boromir stated they did a water change with conditioner last week (post #3) and the fish died overnight Sunday/Monday (post #1) so I don't think it is likely to have been caused by the water change/conditioner.

Aloe Vera doesn't disolve or dissipate in water, even in its "essence" format that is found as part of the ingredients of Stress Coat. It hangs around in the water course, is not diluted in normal water changes.

As a result the build up of Aloe Vera in the aquarium water, although cannot be seen by the human eye, does infact build up in the gills of fish...eventually causing gills to become damaged or blocked. Granted it does take several months of use to get to the fatal stage but since it is poisonous when ingested by animals and humans, it should not be anywhere near an aquarium, especially when there is no proof of beneficial effects in regard to calming or healing fish - as per the label on the bottle.

 

[Naughts]

Aloe Vera doesn't disolve or dissipate in water, even in its "essence" format that is found as part of the ingredients of Stress Coat. It hangs around in the water course, is not diluted in normal water changes.

As a result the build up of Aloe Vera in the aquarium water, although cannot be seen by the human eye, does infact build up in the gills of fish...eventually causing gills to become damaged or blocked. Granted it does take several months of use to get to the fatal stage but since it is poisonous when ingested by animals and humans, it should not be anywhere near an aquarium, especially when there is no proof of beneficial effects in regard to calming or healing fish - as per the label on the bottle.

Totally agree that aloe vera is detrimental to fish, just looking at the time gap then the suddenness of the die off which indicates different scenarios.
We need the OP to answer Colin's questions in post #8.

 

[Back in the fold]

I hate chemicals in fish tanks, they are dangerous and we are not clever enough to know what they are doing to the fish

Truer words were never spoken.

 

[jimwg]

It isn't a hijack at all

You are simply expanding the fact that what we buy is not always what we want or need and that it can have devastating consequences....such as an entire stock in an aquarium dying overnight

I also agree on the Seachem...amongst others.

API Stress Coat is made to sound like the be all and end all in dechlorination with the added "bonus" of calming and healing fish......the truth is that the only thing that MIGHT calm and MIGHT heal is the aloe vera extract but it isn't proven in fish (it is in humans...to emphasise what you have rightly said, @Colin_T )

API products are potentially deadly to fish by virtue of their human orientated added extras. Their testing kits are good, their fishcare products are certainly not, their products are potentially deadly thanks entirely to their use of human oriented treatment extras like unrefined aloe vera in the Stress Coat and unrefined Tee Tree in their "fix" potions. Aloe vera and tee tree is wonderful for human use but even then they can cause side-effects, they have zero place in fishcare.

A build up of aloe vera and the use of Stress Coat either in accidental overdose and/or alongside another dechlorinator over time WILL result in what has happened to the OP's aquarium.

Stress Coat won't even make chloramine safe which many municipalities use nowadays instead of chlorine. Prime will handle chloramine

 

[Essjay]

Stress Coat makes chloramines safe in the sense that it splits the chloramine and removes the chlorine part. But it does not temporarily detoxify ammonia so that stays in the water until the bacteria/plants have had chance to remove it. And it does contain aloe vera.

API® STRESS COAT water conditioner makes tap water safe for fish by removing chlorine, chloramines ...........

API® | STRESS COAT™

API STRESS COAT water conditioner makes tap water safe for fish by removing harmful chemicals from tap water, and contains the healing power of Aloe Vera to reduce fish stress by up to 40% and heal damaged tissue and wounds.

apifishcare.com