Water has slight brown tint, new fish died

[lmbauer2017]

Howdy,

Last year, my patio pond had crystal clear water 90% of the time. I had a gold fish in it that survived the whole year (but died due to my own mistake... I can explain more if asked). I have a potted tree above the pond which lost all its leaves during the winter, and I was not diligent in cleaning out the pond as they fell in. One month ago, I did a basic cleaning of the pond which consisted of stirring up all the debris at the bottom, pumping out two 5gal buckets worth, letting the buckets sit overnight, then pouring the water back in leaving the collected debris at the bottom of the buckets.

I flushed my bog filter a couple times as well and planted new plants in it and in the pond. Usually all these steps will make the pond water crystal clear, but this year it still has a slight tint to it compared to last year. I let the pond sit for 1 month, and since the plants did not die, I figured it was time to put some new fish in. I put two common goldfish in it. One didn't last more than a couple days (he looked all torn up which I was thinking may have been the other fish eating him once he was dead). The other goldfish disappeared after about a week. I haven't had the heart to start lifting platforms to look for him yet.

After reading around on this forum, I'm thinking they may have been shocked when i put them in? What I can't understand is that my levels seem to be fine! The pH may be a little high, so maybe the fish didn't like that abrupt change... but wouldn't they die much quicker if that was the case?

I guess I'm just asking if I should just drain the pond and really clean out the bottom + bog filter and start over? The color of the water is making me suspicious.

Water Quality (note i'm not 100% skilled at reading the colors, i've posted a picture of them jic):
Ammonia (Pond) 0ppm
Nitrite (Pond) 0ppm
Phosphate (Pond) 0ppm
pH 7.5? 8?
KH/GH will be receiving this test kit tomorrow
Brand: API Pond Master Test Kit
Haven't tested my tap water (but I will). I use a "BoogieBlue" garden hose filter for chlorine/chloramine (this normally used for brewing worm tea).

Water temp: ~75degF (no wide swings outside yet)
Size: ~35gal, running for 3 years (no formal cleaning, just stirring up the bottom and letting it settle in 5gal buckets)
Water was replaced (accidentally) about 9 months ago, before that I've never changed the water as it never had any (noticeable) issues
7gal bog filter (1/3 fist sized, 1/3 golfball sized, 1/3 pea sized rocks), flushed a couple times/year
no fish - 9 months ago had 1 goldfish for 1 year (pond sprung a leak, I didn't see it, then filled the pond back up with the fish still in it, the fish died... lesson learned)
Aquascape "Maintain" pump bottle. I squirt one pump in every 1-2 weeks
I've never fed the fish
Added 2 new goldfish recently, one died after a few days, the other died after 1 week
no medications
The fish that survived 1 week looked lively, swimming around and picking at the rocks.

I'm adding a 12gal addition to the pond to help buffer fluctuations. Will post pics when it's complete

Latest pictures of the pond (post fish death):

And here's what the pond looked like 1 year ago:

Let me know if you'd like any more info. Thank you all for your help!

 

[JRS]

Thanks for a very thorough presentation of your issue, very helpful. Curious as to why you think you shocked them when you introduced them. Did you acclimate them too fast?

Minimum would be floating the bag for at least 15-30 minutes to let the temperature equalize. Better yet would be to slowly add some pond water at intervals to the bag or bucket after temperature equalization to chemically acclimate them.

Does the pond get rained on? That would add freshwater to counteract evaporation and would be a natural water change if substantial. The tinted water is what I would expect from the tannins of the leaves, especially if you are adding it back in. Will be interesting to see your KH/GH. If no rain, just tap water?

Any chance of predators being responsible for your missing fish?

 

[lmbauer2017]

Thanks for a very thorough presentation of your issue, very helpful. Curious as to why you think you shocked them when you introduced them. Did you acclimate them too fast?

Minimum would be floating the bag for at least 15-30 minutes to let the temperature equalize. Better yet would be to slowly add some pond water at intervals to the bag or bucket after temperature equalization to chemically acclimate them.

Does the pond get rained on? That would add freshwater to counteract evaporation and would be a natural water change if substantial. The tinted water is what I would expect from the tannins of the leaves, especially if you are adding it back in. Will be interesting to see your KH/GH. If no rain, just tap water?

Any chance of predators being responsible for your missing fish?

I did let the bag float, but I read somewhere if they’re going into a pond it may be best to slowly add pond water to let them acclimate. I never did this before, but was just curious if that could’ve been the cause.

So I’m in south Texas where the pond will lose an inch/day in the summer. It rains often some months, but not nearly enough to counteract how much tap water I have to replenish. That’s why I bought the chlorine filter to help as much as I could. But once again, my previous fish lasted at least a year using this method (and probably would’ve continued to live had my pond not sprung that leak and my poor handling of the situation). But the constant refilling definitely pushes the GH up high, measured from test strips last year. The liquid test kit is a brand new addition to my arsenal as before it was never necessary.

I’ve def thought about predators. Mainly my cat that likes to drink from it. But he’s neverrrr even stuck his paws in the pond so I’m hesitant to think it’s him. It IS suspicious how battered and torn the first fish was… I’m going to search for the second fish corpse today when I get home… if I don’t find it… then he (or a neighborhood cat) must be the culprit >.<

 

[lmbauer2017]

Ok... here are the GH/KH values:
dKH = 8 (143.2ppm)
dGH = 10 (179ppm)

These values seem fine?

I looked for the dead fish, but found nothing hidden under any of the platforms in the pond. It was dark, and I was using a headlamp, so I'll look much harder this weekend when I can be around during the daytime. The fish died a couple weeks ago though so... he may have decomposed/been eaten already?

One crazy thing I found were these black bugs at the bottom that look kind of like a mantis. I've seen them occasionally (for the first time ever), but I thought they were a dead decomposing bug that fell in. Today I saw them MOVING! It freaked me out honestly lol, they're huge (~3in long). I put them on iNaturalist and someone identified them as dragonfly larvae. Awesome beneficial insect that I'm happy to have... BUT... after some Google searches... it turns out they actually eat small fish! There are at least three of these larva in the pond, and I've never seen them in there before. Do you think we may have found the culprit? Should I create a new post in the fish section of this forum?

 

[JRS]

That is a decent range for those parameters. If they are very low, which yours are not, there can be large pH swings causing stress to the fish. Not sure how large a fish those larvae can tackle. How large were yours?

 

[lmbauer2017]

That is a decent range for those parameters. If they are very low, which yours are not, there can be large pH swings causing stress to the fish. Not sure how large a fish those larvae can tackle. How large were yours?

Definitely small enough for them to grab from watching some video demonstrations lol. They were maybe 1.5inch long, very small. I’m going to remove (or snip in half) all of them this weekend, I have plenty of dragonflies. Then get a couple more goldfish and see if they survive