Good tank gone real bad

[Digiphile]

Hi everyone, I have a 29 gallon tank that has been set up for about 4 years. I had 3 black telescoping goldfish (all were small and added a month ago), 8 neon tetras (had for over 9 months), and 1 Pleco (have had for about 5 months). All fish had been healthy. Two months ago I changed the gravel and all of the fish survived fine, the water still turns a little yellow a day or two after water changes though. One of the goldfish developed cloudy eyes so I added Melafix as per the instructions. (I already do 15% water changes w/ gravel vacuuming 1 or 2 times a week). Now, within 4 days all but one goldfish and the pleco were dead! I cannot figure out why and now the last goldfish is acting funny, he sits at the bottom in a corner, behind some artificial plants, until I open the hood. The pleco seems fine.

The water specs are as follows:
Ammonia = 0
Nitrates < 20
Nitrite = 0
pH = 7.6
Alkalinity = 300 (kinda high but I don't know how to fix it)
Hardness = 150

I feed one algae tablet per day for the pleco and give flakes, pellets, or occasionally bloodworms to the rest for food.

Except for the Hardness and alkalinity (which don't seem to be that big of a deal from what I have read) all of these parameters look like good water to me. I don't see that I have over-stocked the tank either. Since the deaths began, about two weeks, I have been doing 25% water changes w/ gravel vacuuming every other day but that still did not stop it. My only thought is that maybe my bio-wheel has run its course (about 3 years old) and it may be time for a new one but that does not seem likely to me.

Any suggestions that you guys have would be much appreciated because I am absolutely stumped. I do not want to add any new fish to the tank until the situation is resolved for fear of wasting money and fish.

 

[Zagz]

How old is your test kit? Your parameters look fine to me, so as long as your test kit isn't old that would not be the problem I would guess. Is there any chance a contaminant could have gotten into the water? Such as a spray cleaner? What temp is the tank? Any temp swings recently? Do you add dechlorinator when you do water changes? Sorry for all the questions, just trying to narrow down the possibilities.

Welcome to AA btw. Glad to have you here!

 

[Devilishturtles]

In addition to the menagerie of questions, what kind of substrate did you switch to? Did you rinse it well before adding it to your tank? How did you do the switch out? It does sound like possibly your test kit could be giving you whack readings. Getting it tested at your LFS will tell.

Welcome to AA!

 

[Digiphile]

I have 2 test kits, 1 which is a few years old is a Master Test kit by Aquarium Phamacueticals. The 2nd which is 3 months old is the test strips made by Jungle. The closest fish store that I have is a PetSmart and they use the Jungle brand test strips as well. I do use a spray cleaner on occasion but I have an Eclipse 3 system which completely covers the tank except for 2 holes in the back for cords and airlines and 2 vents in the top. The spray cleaner I use is made by python

The substrate used to be a mix of black and blue aquarium rock (mixed about 90 - 10), now it is a more natural brown, pea type gravel that I bought at PetSmart. I did rinse it, while shifting it around with my hands, until I could no longer see any color in the water that was running out and then let it soak for part of an afternoon. When I switched from old to new I took the fish out and put them in a 5 gallon bucket with some aquarium water in it and scooped out as much of the old gravel as I could. This proved to make the tank water pretty disgusting, so I let my Eclipse 3 system filter the water for a couple hours before putting the fish back in.

Some extra info (in case it helps) my tank temp is set to 80 - 82 F, and I use Aquasafe by Tetra to condition my tap water and Easy Balance by Tetra to regulate the tank. I only use the Easy Balance on occasion because of the frequency of my water changes.

 

[Zagz]

The AP test kit will be no good IMO. The test strips are better but can give inaccurate readings. I would get another AP master test kit and recheck your parameters. I would suspect that to be a likely cause.

 

[Menagerie]

Welcome to AA, Digiphile!

I'm not convinced it is water related. There are many factors to consider. First, you have tropical fish (tetras) in with cold water fish (goldies). Second, did you quarantine the goldies before adding to the tank? Third, you said the tank has been set up for 4 years, what has been living in it during that time? Have any fish lived for over a year in that tank?

Easy Balance by Tetra

Easy Balance® – Detailed Description of Individual Product Features

* Carbonate Hardness Additive– The appropriate amount of carbonate hardness is added to the aquarium water compensating for KH losses, which occur as a result of nitrification.
* pH Stabilization– Stabilizes the pH value on a sufficiently high level, preventing a drop to biologically harmful levels (pH crash) and produces a certain amount of CO2 preventing excessive pH values.
* Phosphate Removing Effect– In a standard aquarium (30gal) the phosphate concentration is reduced to zero during most of the 6-month period.
* New Feature: Nitrate Reduction with Nitraban™– Serves as a nutrient for denitrifying bacteria that consume the oxygen releasing nitrogen from the aquarium. On average the nitrate concentration will drop below 40mg/l.
* Other Features Include– Production of Carbon Dioxide, the addition of trace elements and a replenishment of vitamin B


8O How long have you used this product? I would throw this product away. Regardless of whether or not this product has upset the tank, it is useless. You already do PWC, which covers a lot of what this product claims to help. Furthermore, I never recommend any product with a pH stabilizer. There is no such thing as a perfect pH, only a stable pH (which your tank has with proper tank care).

 

[Digiphile]

I do not have a quarantine tank so that was not an option.

I have had Tiger Barbs which I traded in because they were causing too much havoc, I had one Betta for 1 1/2 years and a second one that I had for 4 months and then died died (fin rot I think) and was replaced by the goldies. I had 4 bronze corys but they "mysteriously" started dying when I added the pleco. I had them for well over a year. The Neons had been doing just fine for a long time before I added the goldies, and continued to do well a good while until this started. I have always heard that if you could keep Neons for any length of time, then your water must be pretty good. I have also had various others.

I will go and get a new test kit this evening and see if it varies from my other ones.

Thanks for the help and if you can think of anything else that I might be over looking then feel free to respond.

 

[Zagz]

The reason I had asked about the temps in my earlier post is because the goldfish prefer temps of 72 or so degrees and tropical fish prefer the 78-80 range. How long was it exactly from the time you added the goldies? Even if it was a couple of weeks the goldies could have brought in an illness. I would still confirm the test results of your parameters.