What In The World Killed My Fish?!

So long story short I came home today to my recently bought fish dead as a doornail :*(. I have a couple issues with this other than my fish not getting to live a long and happy life. Some stuff happened before his death today that leaves me kind of stumped and I'll explain that in a bit. Mostly I'm writing this because I want to know if anyone can tell me

-Why he died, or what he died of
-If there's anything I could have done better
-How to keep this from happening to a future fish

General timeline of events:
I got my betta on October 11th, 8 days before writing this. Overall he seemed pretty healthy despite having been at Petco for at least 3 weeks and swimming in a shocking amount of poop. The only thing I noticed with him was some slight loss of coloration along his body. Other than that, he was fine. Perky, no fin rot, neither bloated nor emaciated, etc. He went into a planted 20 gallon long that had been up and running for over a month if I remember correctly. I thought (wrong apparently!!) that it was cycled. The old heater maxed out at about 72˚F.

Oct 13th I got him a new heater because I noticed he was rather lethargic and unenthusiastic about food (although he would eat a bit) and blamed it on the temperature. Visually, he was looking really nice, so I didn't really think he could be sick. His color had gotten deeper and was starting to cover the parts that had faded during the time at Petco. The new heater was adjustable so over the course of several hours I gradually raised the temp to 76˚F.

Between October 13th and 16th he was still rather lethargic and getting even more disinterested in food, and, being a big ding dong, I started blaming his state on a number of other things which I went about changing instead of doing the smart thing and testing the water already. I baffled the filter (in hindsight, should've done that earlier...), adjusted the plants to give him more hiding spots (which the snob never bothered to use), made a new hood for the aquarium (I thought the cats might be sitting on the top and maybe that could be stressing him out). Other than the lethargy, I noticed he was panting a bit.

October 17th I finally checked the water parameters. Nitrites were at FIVE and nitrates around 80. I don't even know what ammonia was at. So after having an out of body experience, I did a load of water changes, eventually getting the nitrites down to 1-3 ppm and nitrates between 20-40.

October 18th (day before posting this) I was more than a bit worried about how long I would have to be doing water changes before the cycle would reach a state of more stability. My poor fish was still panting and starting to look a little...round...despite me fasting him (although it's possible he was chowing down on fruit flies, which have a tendency to commit suicide in any water they can find in my house). No pineconing though. Just a bit chubby. And no swim bladder problems either. Nitrites still hovering around 1-3 ppm.

So later on October 18th I moved him over to my spare 5 gallon hospital tank with nitrite-free waters while the conditions in the 20 gallon stabilized. I heated it to a toasty 80˚F. After being transferred in, his behavior changed notably for the better, so I got my hopes up a little bit. Swimming around, investigative, I even got him to flare, which he wasn't doing before. Before going to bed, I covered the sides of the tank in paper so the cats wouldn't bother him during the night.

If he had just died then and in that state, I would've blamed it on nitrite or ammonia poisoning and wouldn't be writing this. But somewhere along the night there was a bit of a strange development that I don't know what to think of. I checked on him this morning (October 19th) and he looked awful. Fins clamped, stationary, and covered in a really weird goop, for lack of a better word. It wasn't fuzzy, and didn't have any particular color to it. It just looked like ointment or something. The only positive developments were that he wasn't panting and didn't look bloated anymore.

Goop description: whitish but mostly transparent. It is mostly on his fins and there's a bit on his head. It doesn't look fuzzy like a mold. I think the best way I can describe how it looks is like a layer of weird ointment. When he moved, it came off in chunks. I haven't been able to find a picture online that looks like it. I honestly have no clue what it is or why it only appeared in the morning. That's the thing that confuses me so much – I have no idea what it was or how it appeared so fast. I really don't know if it was the move to the 5gal that caused the goop attack, the temperature change, the lack of light from the paper, etc. The water in the 5gal is from the same source as the water in his home tank, so aside from lack of nitrites and nitrates the parameters were identical. Yes, I tested it.

I papered up the tank again and went to school. When I got back he was super duper dead. Most of the goop fell off him but he still has quite a bit on him. The goop and the...deadness...were the only things of note about him. No pineconing, red streaks, red gills, fin tears, etc. I can't even express how sad and confused I am about this whole thing. I'd barely had the poor boy for a week, and now he's dead? I want to get another betta, because if I don't all this food will go to waste and I'll just have an empty tank, but I don't want to get another one without understanding what happened and what I can do to have this not happen to my next fish. I want to adopt a fish, not put him on death row, if you get what I mean. So that brings me back to the questions I had from the beginning:

- What killed my fish?!
- If I could go back, what could I have done better (besides making sure the tank was cycled and testing the waters earlier. That I know)
- How do I make sure this doesn't happen to my next fish? Do I need to sanitize everything or what?!

Side note: if you've bothered to read this far, thank you so much. I know it was a bit wordy. I tried to include a lot of detail because I figured I should be as thorough as possible if I want someone to take time out of their day to help me with this pickle.

 

I don't have any advice but want to say I'm sorry about your fish.

I hope the forum members can help you solve the mystery.

 

HI there, and I'm so sorry your guy didn't make it. Sadly that is the case with a lot of fish that come from Petco/Petsmart.

One question, because there is absolutely no way a betta made such a big mess of a 20 gallon tank by himself; what other fish/animals/inverts/whatever are in your 20 gallon?

The ointment looking stuff you saw on the betta was most likely his slime coat having issues. Sometimes when a fish is really sick, this can happen. The slime coat is their first line of defense, and I've seen it become inflamed, for lack of a better word, on occasion.

Also a thought just occurred to me; how did you acclimate your betta to the 20 gallon?

 

- What killed my fish?!

Sounds like you bought a likely sick fish, put him in an uncycled tank along with the stress of acclimation, which made him sicker and then he died.

- If I could go back, what could I have done better (besides making sure the tank was cycled and testing the waters earlier. That I know)
- How do I make sure this doesn't happen to my next fish?

First don't buy a fish from an unhealthy looking tank, don't put a fish into an uncycled tank without keeping up with the water changes. And make sure you test water more if the tank is uncycled.

 

Sorry to hear about your fish . Sounds like he may have had slime disease, caused by a parasite. Symptoms are lethargy, excess mucous production (which, if it covers the gills causes labored breathing). Here's an article about it:

 

HI there, and I'm so sorry your guy didn't make it. Sadly that is the case with a lot of fish that come from Petco/Petsmart.

One question, because there is absolutely no way a betta made such a big mess of a 20 gallon tank by himself; what other fish/animals/inverts/whatever are in your 20 gallon?

The ointment looking stuff you saw on the betta was most likely his slime coat having issues. Sometimes when a fish is really sick, this can happen. The slime coat is their first line of defense, and I've seen it become inflamed, for lack of a better word, on occasion.

Also a thought just occurred to me; how did you acclimate your betta to the 20 gallon?

HI Junebug, thanks for taking the time to read and answer, I really appreciate it.
First off, yes he's the only pet I had in the 20 gallon. Quite literally nothing else but plants in there, which is part of why I didn't suspect a spike in nitrites so soon. I don't know if this could have been related, but I feel like I should mention the substrate. I don't still have the bag, so I can't tell you exactly what it said, but it said something about being active or having bacteria to help start your tank's cycle. About a day after I put in the substrate, I tested the water. There was a (low) reading of nitrate. Nitrite tested zero or measured too low to show on the test. So I don't know if that tidbit helps or not. Water straight out of the tap at my house reads zero ppm on both nitrite and nitrate.

About how I acclimated him: I used a really tiny syringe thingy (not the needle tipped kind, the kind that you use to give oral medication to animals. But don't worry, it was brand new) to suck the poop from the bottom of the cup and I threw that away. After that, I used a fine tipped baster to take water from the main tank and drip it slowly into the cup. I would do this until the cup was almost full, throw out half the water, and continue dripping in water from the main tank. Did this for about an hour and then held the cup slightly underwater in the main tank until he swam out. I don't know if this is an official acclimation method, it's just what we've done in my family, so feel free to lecture me if I've been doing this terribly. I did the same thing in transferring him to the 5 gallon, except I did it for longer because he was already looking bad and I thought taking things slow would avoid stressing him out even more.

 

Sounds like you bought a likely sick fish, put him in an uncycled tank along with the stress of acclimation, which made him sicker and then he died.


First don't buy a fish from an unhealthy looking tank, don't put a fish into an uncycled tank without keeping up with the water changes. And make sure you test water more if the tank is uncycled.

HI TwoHedWlf, thanks for reading and replying. I'll be sure to test my water more often in the future.

I'd like to reassure you that I don't ever intend to put fish into uncycled tanks. The fact that he ended up in a tank that wasn't done cycling was a mistake on my part, but one that I was unaware of. I didn't buy him knowing that I might be putting him into harm's way, and especially after this experience, I never want to buy a fish without being absolutely sure it's done cycling and can handle the addition of a fish without becoming dangerous.

 

I'm sorry to hear about your fish. It is difficult to tell without pictures exactly what was goin on with your fish. I have seen slime coat issues be confused with a strain of columnaris. Good luck with your next buddy.

 

Sorry to hear about your fish . Sounds like he may have had slime disease, caused by a parasite. Symptoms are lethargy, excess mucous production (which, if it covers the gills causes labored breathing). Here's an article about it:

Sorry to hear about your fish . Sounds like he may have had slime disease, caused by a parasite. Symptoms are lethargy, excess mucous production (which, if it covers the gills causes labored breathing). Here's an article about it:

Hi, thanks for taking the time to read. I did some reading on slime disease, but I'm really not sure about if that could've been it. The onset of the goop was really sudden, like less than 12 hours and I'm not aware if that's possible with slime disease. I also didn't see any goop on his gills, it was mostly just sloughing off of his body, analfin, and caudal fin. Not much on the head. With these inconsistencies, I'm a bit reluctant to pin it on slime disease. But thanks for the article anyway, I'll definitely keep that link for use in the future.

 

I'm sorry to hear about your fish. It is difficult to tell without pictures exactly what was goin on with your fish. I have seen slime coat issues be confused with a strain of columnaris. Good luck with your next buddy.

Thanks for the kind words, KimberlyG. I really wish I could've gotten a picture of the slime when he was still alive . I did intend on taking a picture eventually, but I didn't expect him to be dead within the day.

 

It's possible he just had a disease (LOTS and I mean LOTS of bettas come home with diseases you can't see for a few weeks). My suspicion would be he had some sort of epithelial infection which caused his slime coat to overproduce and slough off. Unfortunately without pictures, we have no way of knowing what it was. I do know that it wasn't anything to do with your tank, if he was the only inhabitant. Even if the water conditions were off, bettas are really hardy because they don't breathe much through their gills, and can get air above the surface if water conditions are bad.

I also find it really odd that your nitrite skyrocketed. With no fish in the tank and only plants, the plants should be gobbling it up. I would let the tank run for a few weeks before adding any more fish to it, and make sure you check it for dying or dead plants.

 

It's possible he just had a disease (LOTS and I mean LOTS of bettas come home with diseases you can't see for a few weeks). My suspicion would be he had some sort of epithelial infection which caused his slime coat to overproduce and slough off. Unfortunately without pictures, we have no way of knowing what it was. I do know that it wasn't anything to do with your tank, if he was the only inhabitant. Even if the water conditions were off, bettas are really hardy because they don't breathe much through their gills, and can get air above the surface if water conditions are bad.

I also find it really odd that your nitrite skyrocketed. With no fish in the tank and only plants, the plants should be gobbling it up. I would let the tank run for a few weeks before adding any more fish to it, and make sure you check it for dying or dead plants.

Junebug,
I think you're probably right about him coming home with a disease that just wasn't visible for a while. Also, I tested the water in the main tank today. Nitrites have dropped to 0.5-1 (compared to 1-3 on the last reading) and nitrates are still at 20-40, the same as they were when I last tested the water. I haven't changed the water since the 18th, the day I moved my fish out of that tank. Is the drop normal?

 

Yep, the plants are eating up those nitrites. If you leave the tank unfertilized for a few weeks you'll probably see nitrites at 0 and nitrate dropping too.