Any fish people out here? I need advice

I am at my wits end. I’ve kept small fish, usually betta, for quite some time now. Always had good luck. But over the last ~18 mos or so, I cannot keep anything alive. I killed goldfish, for pete’s sake. Who kills goldfish?? So I decided to try some guppy. I’ve now killed 7, in about 2 weeks time.
The only common denominator here is a water change! I am on city water. I use a tap water conditioner. I test my pH.
Most recently after the goldfish died, I completely emptied the tank. Refilled it with plain tap water (again, city water) but I did not treat it. I just left it to cycle and ignored it. After a couple weeks I decided to try again. I tested the pH of this plain water and it was at a perfect 7.0. I added some Stress-Zyme and got 3 guppies. For the first week they were fine. I did a partial water change and within 24 hours they were all dead. The water was treated with water conditioner prior to being put into the tank, but it didn’t sit for a week, so basically it came straight from the tap, into a bucket, into the tank.
I tested my pH again and now it’s at 6 or less, the (test tube) color is yellow. In the past when I’ve tried to adjust my pH up, using pH Up does nothing. The only thing that has worked is a pinch of baking soda. Apparently my tap water is going thru wild pH fluctuations??

WTH is going on??? What can I do??? I’m tired of killing my fish! And it’s getting expensive!

I’m a freshwater wildlife biologist- there are many, many water quality parameters which can impact fish health outside of pH. Chlorine isn’t good for anyone (since you mentioned "city water) and it’s byproducts are even worse. The most common issues we have in hatcheries are ammonia, salts sneaking in, conductivity, and nitrates. Do you have the ability to take a water sample somewhere to test? Used to be that pet store type places used to run basic water panels for aquaria that had a little more information?


I would be concerned that your tank isn’t fully cycled. How big a tank? Smaller ones are a lot harder to maintain that bigger ones. I wouldn’t worry to much about the PH, most fish are pretty adaptable to different PH levels.

I 2nd the idea of taking a water sample in for testing. Any pet store will do it, but a fish only store will probably be more helpful with correcting the problem.

I’m also on city water, I use Seachem Prime as my water conditioner. It’s a bit spendy, but I only use 1/4 tsp per 5 gallons of water. I also use Seachem Stability to give the good bacteria a boost.

For goldfish specifically, a good filter is a must! They producer a LOT of waste products.

Bettas and guppies will do much better with a heater as well. Goldfish don’t need one.

OP, sorry about your problem & I’m no help.

I have a question for @wildlifer :slight_smile: I’ve
kept goldfish (25¢ feeders) in a stock tank in my back yard for nearly 15yrs.
Originally fish were meant to keep my horses’ plastic barrel trough clean. Fail!
Survivors migrated to the yard, starting with a 1/2 barrel & brought inside to an aquarium in Winter.
When the 3 I had got cramped in a 30gal tank, I got a 65gal aluminum stock tank & left them there year-round with a circulating pump & floating de-icer.
They flourished like that for ~5yrs.
Largest was nearly a foot long, the other 2 not much smaller, when I upgraded to a 160gal tank.
Filled from my outdoor well water tap, so no chlorine,. Well is high in iron, but I’d refilled the tank annually w/o a problem. Every Spring, fish went in buckets while I scrubbed & refilled the tank.
Within a week in the new tank all 3 were dead :skull:
I dumped, scrubbed, refilled & got 6 new feeders.
2yrs later they’re fine, largest is 6"+, others at least 4".
What killed the older fish? :female_detective:

Old age? They were 20+ years old, right?

I agree with what @Pep_n_Ann said. Invest in a good water testing kit. I also use Seachem water conditioner and Prime that adds good bacteria. Also, goldfish grow to be huge and are a very dirty fish. They really do best in really large aquariums or ponds. I’ve not had much luck with guppies either. I’ve had better luck with platys and the Glo tetras.

:laughing: My 15yrs of fishkeeping includes the last 2(3?) with the new guys.
AFAIK, the oldest of the Sudden Death fishes was at least 10. Dated from an old COTH thread on using goldfish in troughs.
And being “koi” (= carp) 20 is teenaged :smirk:

oh sorry I added up the numbers in your post and the “feeder fish” description and thought they were the same fish

My “koi” were feeders to start.
They grew to fit the tank :open_mouth:
The new feeders look to be headed the same way
The Old Guys, about 8yrs in:


2dogs, hard to say for sure. As you discovered, fish don’t keep tanks cleaner, fish excrete ammonia & nutrients, which in turn just feeds algal growth. Fish are easily subject to water “shocking” if you don’t temper them, so if you move them from a bucket to a tank & it’s not exactly the same water at exactly the same temperature, they can die.

Since you said it was a new tank, it’s also possible that the newly made materials released something into the water that was stressful or toxic to the fish. Both plastics & metals could contain blends or coatings that could do that. Maybe it would leach out with time & be ok after the initial fill, maybe not. That’s always a risk with using a container not specifically designed for fish.

Fish can also be suffering sub-lethal effects that you may not notice & then if they get an added minor shock, that pushes them over the edge & they go belly up.

In general, a good approach is to always go gradual if you want them to live - only do partial water changes, add any new water gradually, giving them plenty of time to adjust, don’t subject them to sudden temperature changes.

A fish’s slime coat is also very important to their health/immune system/swimminess(yeah, I just made that a word), so an additive that boosts/protects slime layer is a good idea when there are going to be any changes.

My guess was something leached from the new tank. And, as you suggest, a combo of that & stress may have done the Oldies in.
Though, I did leave some of the old water in the cleaned tank (impossible to completely empty :stuck_out_tongue_winking_eye:) & buckets were 1/2 old tank, 1/2 from the tap
IIRC, I only waited about a week before getting the replacements, so whatever could have been non-toxic by then. :woman_shrugging:

Swimminess :face_with_hand_over_mouth:

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It’s a 10-gal tank. Originally, only for a betta. The goldfish were small feeder, there was 2, and they lasted like 48 hours. So them being a “dirty” fish had nothing to do with it.
It has a heater and a filter, both appropriate for the size of the tank, both adjustable temp/flow.
I also use Seachem, if I can’t find it I use API.
I’ve googled everything I can find, no help beyond what I already thought of. I have a water testing kit that does nitrates/nitrites, etc., and everything has tested fine.
I will try to find a ‘fish only’ pet store and see what they say.

I’m no fish expert, but I would assume it’s what the city uses to treat your water that is the problem. If it having sat in an open container for a week helped, and changing without having had the water sit killed them, I would assume chlorine. There is another chlorine-like compound that they can use that will not off-gas and you can’t use it at all for such, I’m trying to remember why I know this…oh! From fermenting chicken feed way back when. So, I would try only using the water after you’ve let it sit out for a few days or using different water.


If you have a decent local fish store most likely going to be a saltwater fish store you can buy some plain RO (reverse osmosis) water from them to do a total water change. Add your water conditioner as normal and try again. If you manage to kill them with that water it isn’t the city water that is the issue but something else. I also agree that if they did fine for awhile after being in water that sat for a bit tells me that the city water could be a major part of it. If that is the case simply leaving your future water change water sitting in a bucket for 24ish hours will help with that.

@pick_a_pony has a good idea! Make sure to leave the gravel and filter media alone so you don’t destroy your good bacteria and need to cycle the tank again.

Yes, chloramine. That one you have to use chemicals for.


Cycling a tank requires ammonia to build up good bacteria in the filter and substrate that will convert nitrites to nitrates. You can do this by adding a shrimp, using a quick start product or slowly stocking your tank with fish that will likely die but you need to be testing every step of the way. The ammonia needs to build up for that to convert to nitrites, with both being harmful to the fish, and then eventually the “cycled” filter will convert nitrites to nitrates, which is less harmful. When a testing kit shows nitrates, you do a partial water change and add the fish. It sounds really complicated but once your tank is established it’s pretty easy to maintain.

Are you acclimating the fish by slowing adding your water to what they came in, and making sure the temperature is really close before putting them in the tank? I had a small tank or bucket where I would keep them for a day and add a cup of new water every 30 minutes for a few hours then start removing a cup for every one added until they were mostly on my water without showing any stress.


Yes to all of that. When I emptied the tank, I don’t mean I dumped the gravel too. I just sucked out as much water as I could. So, there were still bacteria in there. When I do a water change, I will add a little bit of quick start or Stess-Zyme.
At any rate, I have one lonely guppy hanging on. Fingers crossed.

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The good bacteria will die off if there’s nothing to feed it so an empty tank will go back to square one after a few days and spike when you add fish again. Have you been testing to see where the tank is in the nitrogen cycle?

For one fish I would do a big water change and add aquarium salt if he has no obvious illness. If he looks even a little off, use Melafix. I always did both as a precaution when getting new fish.

Sorry, I did miss that above!

What you want is to see an ammonia spike that turns to nitrites (ammonia will zero out) and then to nitrates at which point both ammonia and nitrites should be zero. It’s not uncommon for this to take 6-8 weeks and there will be ups and downs until it gets there. IOW, a result of no nitrates in a random sample doesn’t mean a stocked tank is good unless you know the other two are zero after a week of no water changes.

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