Oh no.. loosing fish in my 20 long!

[FreshyFresh]

History on the tank:

Tank has been established and stocked since Jan/Feb of this year. Did a very successful, but frustrating fishless cycle on it. Stocking was 10 neons, 5 blood-fin tetras, 4 emerald corys, a female black molly, a really tiny honey gourami and two mystery snails that have recently had babies. The deaths I had early on were several neons and one cory w/in a day or two of purchase, then a bad case of ich, but since then, all has been awesome since Feb/March.

I do weekly ~50% water changes on this tank (never missed one) and my water params are always 0,0,20 per my API master test kit. I use Seachem Prime for a dechlor, maintain 76-78F water temps and feed flake food 6 days a week and little sinking shrimp pellets for the corys.

This Monday AM I noticed my poor black molly puffed up like a football, with scales sticking out like a pineapple. Dropsy maybe? Oh no.. I go down to the computer to research. Minutes later I go back up to check on her and she was already dead.

Tuesday AM I notice a bunch of tiny golden mystery snails. I have clutches of eggs laid under the plastic LED light hood. Everyone looked great in the tank, but the water had a very slight milkiness to it.

Today (Weds), I wake up to a dead blood-fin and a dead neon! I tested my water params and they were 0,0,40. I did a 80-90% water change on it.

I can't imagine what's going on? I do have a 2yr/old in the house and have considered a contaminant getting put into the tank, but have no idea for sure.. Any ideas?

 

[Thyra]

What about feeding? Has one of the kids been feeding either fish food or something else on the sly? That could account for the rise in nitrates. Is the 2 yr old the only suspect? Like, would the others tell you if they fed or put something in the tank? I assume there is a lid on the tank. Is there a way to secure it?

 

[FreshyFresh]

Good call there, but the food and supplies are kept way up out of reach, plus my kids have never really shown any interest in feeding, etc. They like to look at them and know I'm quite anal about the whole deal. LOL!!

The cheap-o Top-Fin LED hood covers the whole top aside from a credit card sized hole for feeding.

Thanks Thyra, I'm really stumped on this one.

 

[Thyra]

Remember, Joel, you got to "think" like a kid. Sometimes they do something suddenly that they never showed any interest in doing before - like, I remember my Mom saying, "Whose bright idea was this??" Any chance anyone sprayed for insects or for cleaning anything? Sometimes we never figure these things out. Do you have any decor in the tank that could be deteriorating? I have some fake ceramic hollow stumps that the paint has flaked off - in my case it didn't hurt the fish, but it was a mess.

 

[FreshyFresh]

Still racking my brain as to what happened here. Lost another neon this afternoon. All the remaining fish look/act fine. Did another 50-60% water change. Heater and filters all functioning as they always have.

Like I say, it all happened after a routine weekly water change. I did do a somewhat aggressive gravel vac, but it's not unusual for me to do so. This tank is always pretty clean, given my weekly ~50% WCs and the fact I've got an AquaClear 30 HOB and two sponge bubbler filters in it.

This is the cursed tank. This was originally the 29g that split across the back out of the blue on me.

Remaining fish in it: 8 neons, 4 blood fin tetras, 4 emerald corys 1 honey gourami.+ mystery snails.

 

[Guanchy]

do you think that maybe the water u used when you did the water change had something in it? maybe something fell in it without you noticing. Or something in your sink

 

[FreshyFresh]

Thanks G.

I thought about that too. My 20 is the last of my three tanks I do WC's on and the other 2 have been fine. Same stuff used for all 3. So far so good. All the remaining fish appear to be doing fine. Water params 0,0,10.

 

[OrangeCones]

Do any of the neons have any fading of colors, looking like bleached in areas, especially where the red and blue color meets?

 

[FreshyFresh]

On the last neon I lost, I noticed it not hanging with it's school. Colors looked good, but it wasn't behaving like the normal healthy neons I've had. An hour or two later it was dead sucked to the filter intake.

What's your thoughts on color fade?

 

[OrangeCones]

Trying to rule out 'Neon Tetra Disease,' which is sadly becoming more common in mass produced fish.

 

[FreshyFresh]

Trying to rule out 'Neon Tetra Disease,' which is sadly becoming more common in mass produced fish.

I did read about that.

This particular batch of neons I've had for about 6-7 months.

 

[OrangeCones]

What temperature do you keep the neons at? Also, what is your water's hardness (KH and GH)?

 

[FreshyFresh]

I have the heater set to maintain ~76F. The tank can hit 80 on a super hot, humid day. Not too often in my area.

I've never measured, nor have a means to measure water hardness. All I have is a standard API master test kit. I've only measured pH a handful of times on each of my tanks and my tap water. That's always reads the highest of the low range. 7.6?

Like I say, I've never missed a weekly water change on any of my tanks, and tend to do 50% or more on my 20 and 10g.

It could have been coincidental, but the whole thing started with a badly bloated molly that was fine on water change day and dead the next. Noticed water slightly cloudy, then lost a blood fin tetra the next day, then 2 neons the day after that. Did large WC's between deaths.

All has been OK since. Water params 0,0,10-20.

 

[OrangeCones]

Neons generally don't do well in higher 'tropical' temperatures. They do best in low-mid 70s. Your heater is set to the high end of where most would agree they should be. However, if your water has been going up due to the weather, that may put additional stress on them, especially if your water is hard. Without testing the GH/KH, there is no way to know what the tank's water is, especially when compared to the new tap water that you are using. When I lived up north, I had widely changing hardness in my local tap water, due to farming activity upstream from where I lived, and recent rain. Neons seem to be especially stressed by hard water and sudden changes in water's hardness (if your tank's water and new tap water used for water changes were vastly different).

Mollies prefer harder water, so they may not be compatible long-term with neons. It would be hard to get the water right for them both in the same aquarium.

If you are interested in testing your water, API makes a GH/KH test kit. My LFS sells them for $9.

Mollies are not known to be stressed nearly so easily by sudden changes in water's hardness. The fact that the molly was the first one sick and dying stumps me too.

 

[FreshyFresh]

Good info. Thanks!

It's been a good 4+ weeks since we've had ~90F and humid ambient temps, but I'll keep an eye on that.

I will invest in a hardness test kit on my next LFS (or otherwise) visit.

I'll lower the tank temp once I look up recommended temps of the current stocking:

1 little honey gourami
4 blood fin tetras
8 neons
4 emerald corys
mystery snails

 

[FishDad]

Bummer Joel, when was the last time you added a fish or a plant?

 

[FreshyFresh]

FD, no new plants or fish. I did have a zucchini disk in there just before the issues that the mystery snails were happily gobbling.

I did swap a couple fish around back when my 29g cracked and I re-set the tank up in a new 20 long. That was months ago though.

 

[WildBohemian]

Do you always wash your hands and arms real good before you put them into the tank? I've known people who forget to do this, and have lotion or perfume on them when they stick their arms into the water, and it killed their entire stock... but with the pineconing you mentioned, it almost sounds like a disease rather than external contamination, but you still can't rule that out... did you quarantine the fish before you added them to the tank? What was your most recent addition and how long ago were they added?... oh, I see... there's a second page! No new fish for months... hmm, what a mystery!

 

[FreshyFresh]

Good call on that WB, but I'm not much of a lotion guy. If anything I could have x-contaminated from my other two tanks, given I did water changes on them just before the 20 long. Thing is, the other 2 tanks have been perfect w/ no new additions.

 

[FishDad]

The fact that the molly was the first one sick and dying stumps me too.

If OC is stumped then I would just chalk it up to an act of God.