Do I need to do something about this?

[natbla]

I picked up a couple small white koi to replace the two that were eaten. All was well for a week. Sometime last evening between 7 PM and 8:30 one disappeared and the other lost one of its front fins. I'm hoping the one fish isn't really go, that I just missed it, but I'm sure it was gotten during the time in question (and a huge thunderstorm). But I only just noticed the other being shirt a fin.

It had both when I bought it, and its still got the one fully functional fin. There is a short stub where the other fin was. There are no marks that I can see (I haven't pulled it out as I don't want to add unnecessary stress) . Its swimming pretty good with only a once in a while tip toward the missing fin side. It goes up, down front and back, but mostly circularly toward the missing fin. Its eating algae of the pond wall and floor fin and even a couple flakes of food that floated down from the surface. Other than missing the fin, its not acting distressed at all.

I'm inclined to leave it alone and not even pull it out for a closer evaluation as it seems OK but for a tendency to go in one direction circles. Should I be more active in treating it? Will the fin "grow back?" Any thoughts would be appreciated.

 

[Oldhead]

Do you have turtles? or is your pond close by another water source that has turtles? especially snapping turtles?

 

[natbla]

Do you have turtles? or is your pond close by another water source that has turtles? especially snapping turtles?

No turtles that I see, and my pond is very clear. I do have bullfrogs. There are two of them still and two smaller green frogs. I got rid of a really big bullfrog three weeks ago. The two remaining have doubled in size so I may get rid of them as well.

 

[HARO]

Bullfrogs swallow their prey whole, so it's unlikely they would be the culprits. Possibly a bird; kingfisher? crow?
John

 

[natbla]

Bullfrogs swallow their prey whole, so it's unlikely they would be the culprits. Possibly a bird; kingfisher? crow?
John

The weird part is that the 2 white ones were there at 7:00 when it started to rain and it rained and stormed hard for 3 hours straight. Major storms with high wind lightening etc. it added 2 inches to the pond. But at 10:30-11 ish I went out and the one was gone. I thought it was hiding. It wasn't until the second time out around midnight that I realized what had happened to both of the fish

 

[Waterbug]

To answer the original question "Do I need to do something about this?" One missing fish and one lost a fin...Hell yeah, you should do something.

What are your water parameters?

 

[natbla]

To answer the original question "Do I need to do something about this?" One missing fish and one lost a fin...Hell yeah, you should do something.

What are your water parameters?

The do something is in regards to taking care of the missing fin fish. I continue to try and identify the attacker, and take precautions. As I stood on my back porch overlooking the pond. I was watching the 5 frogs placidly float or perch on plants and the wall. The goldfish were busy trying to make new fish, and the koi were actively eating algea and fish food but staying down from the top layers of the water. My guess is the predator visited again last night. But no one is missing this morning.

I'm at work so I'm not looking at the results in front of me so here it is by memory from 2 days ago, all parameters were in normal ranges. Please forgive my lack of proper identifying the names of the parameters, I suck at names and terms when not looking at them. Its a good thing I only have 9 staff members names to remember on any given day.

0 Ammonia
0 Nitrate
600 ppm on hardness (can't remember the right term)
7.5 ph
I can't recall the fifth test item but is was also dead on normal range.

Interestingly, the large growth of slimmy algae on the water fall has dissipated significantly over the last 5 days, while the cotton like algae on the pond walls has added about 1/2 an inch to its size. THe fish are mostly eating algea, and I only feed fish food 3 times a week, and end up netting 1/2 of whatever amount I put out. It doesn't matter how much I put out, the fish always eat half.

 

[natbla]

Tonight's readings:
0 nitrate
0 nitrite
8.5 ph
300 alkalinity
300 hardness

75 degree temp

 

[Waterbug]

That's a pretty big swing in pH. I'd be interested in the KH part of alkalinity.

Predators do take fish and you're right to be concerned. However I'm a percentages guy and water quality problems take more fish so I like to cover that base too. Fish new to a pond often jump. Fish new to a pond with a water problem can jump even more. It is not uncommon for a fish to jump out of a pond and not be discovered for several days. Or a cat to come along, find a dying fish on the ground and cart it off. Actually a lot of animals could do that, dogs, possum, snakes, owls, hawks, crows, small children and more.

That wouldn't explain the fin loss unless it was a weird bacteria thing. Peck fins are attached pretty securely. IMO something would have sit there and chew it off. But I can't see it so I have no idea.

 

[natbla]

That's a pretty big swing in pH. I'd be interested in the KH part of alkalinity.

Predators do take fish and you're right to be concerned. However I'm a percentages guy and water quality problems take more fish so I like to cover that base too. Fish new to a pond often jump. Fish new to a pond with a water problem can jump even more. It is not uncommon for a fish to jump out of a pond and not be discovered for several days. Or a cat to come along, find a dying fish on the ground and cart it off. Actually a lot of animals could do that, dogs, possum, snakes, owls, hawks, crows, small children and more.

That wouldn't explain the fin loss unless it was a weird bacteria thing. Peck fins are attached pretty securely. IMO something would have sit there and chew it off. But I can't see it so I have no idea.

The rain we've had in the time between the 2 sets of tests had the impact of the equivalent of a 10-15%% water change, plus the first data was at a water temp of 50 degrees so the temps jumped 50% in 2 days (in the top foot of the water. That said, this is the first time in 10 tests over 5 weeks that I didn't get 0,0, 7.0-7.5, 600, 180 as my numbers (I looked at the log last night).

Also in a 4 day period I've gone from fully aglea covered waterfall with green slim up to 1/4 inch thick in places, and hanging of all rock edges 3-4 inches or more, to a completely clean waterfall as of last night with only minor green on rocks that get splashed on the edges. So the pond's chemistry is definitely in flux at the moment.

I tried to take some pictures of the fish without removing it from the pond, but wasn't able to get any good ones. I'll try again tonight. But since its eating and swimming well I didn't want to add stress beyond the injury.

I had thought about the jumping thing myself (that fish had been in the pond 3 days), but discounted it due to the injury to the other fish. Still with all the rain that night, it would have only had to clear 3-4 inches of height to end up on top of the pond wall when the water level was highest. Seem a bit much for a 3+ inch fish but maybe not.

 

[Waterbug]

Picture of the fish probably wouldn't help, kind has to be looked at in person and even then it can be pretty hard to tell.

Sorry, I didn't realize these are 3" fish. OK, losing a fin in that small a fish is easier. Is there any chance the fin was missing when you got it? Birth defects are very common. But to me that all but rules out predators like Herons...really almost all because of the way they attack. And so small, if they got a hold of a fin the fish would be a goner 99.999% of the time. Ripping the fin out, with a lot of tissue damage would be more what I would expect.. If there were other fish like Bluegills then fin biters would fit.

How big is this pond? A 50% water temp jump in one day...is there a heater in this pond? Or I should say...are there 20 heaters in the pond? I'd have to assume one reading was incorrect.

300 ppm and you get a 1 point pH swing also makes little sense. Is there a pump or some water movement that would mix the water? Your rain is normally in the 4.5 pH range, 10-15% volume of rain, rain is lighter than the pond water so might pool on top without good mixing, take a reading there and you'd seeing all kinds of values.

Don't see how that would explain 75F water.

Bottom line is I think more practice or care is needed in taking these measurements. Not saying that IS the problem, just that it is a very common problem.

 

[natbla]

Picture of the fish probably wouldn't help, kind has to be looked at in person and even then it can be pretty hard to tell.

Sorry, I didn't realize these are 3" fish. OK, losing a fin in that small a fish is easier. Is there any chance the fin was missing when you got it? Birth defects are very common. But to me that all but rules out predators like Herons...really almost all because of the way they attack. And so small, if they got a hold of a fin the fish would be a goner 99.999% of the time. Ripping the fin out, with a lot of tissue damage would be more what I would expect.. If there were other fish like Bluegills then fin biters would fit.

How big is this pond? A 50% water temp jump in one day...is there a heater in this pond? Or I should say...are there 20 heaters in the pond? I'd have to assume one reading was incorrect.

300 ppm and you get a 1 point pH swing also makes little sense. Is there a pump or some water movement that would mix the water? Your rain is normally in the 4.5 pH range, 10-15% volume of rain, rain is lighter than the pond water so might pool on top without good mixing, take a reading there and you'd seeing all kinds of values.

Don't see how that would explain 75F water.

Bottom line is I think more practice or care is needed in taking these measurements. Not saying that IS the problem, just that it is a very common problem.

The pond is 900 gallons and 10 X 6 square fed by a waterfall and 2 blue totes that serve as settling tank and filter. They are above ground and enclosed so that might have helped increase temps. Also its a floating pool thermometer so it could have warmed somehow. But the water feels very warm to the touch. The air temp has gone from 55 in the day to 3 straight days of 90 degrees during the day and 70 at night. I am measuring at the top water layer, and the bottom foot and a half are below the intake of the pump so there maybe some some temperature striations going on. The surface water has a circular flow to it in general. The ornamental grasses that provide shade are not yet tall, and my water lilies are less than 10% of the surface so far.

I looked fish over before I bought it pretty good, and at the time it had all the appendages. For that matter, one if the reasons I purchased 2 match white koi was the body symmetry of both. I wonder if my big 9 inch and 6 inch goldfish would have taken a bite at it?
The part missing is the "fan" not the arm of the fin.

I agree, that I need more practice on monitoring being new to it. That said, I'll check things again tonight after work at about the same time as last night to see what I have for numbers. Those new numbers were the first readings ever like that.

 

[Waterbug]

Oh, the fan, not the arm...I get it now. The arm is boney and I couldn't figure out how that could be lost.

Yes, sure, larger goldfish can bite new fish. Not super common, but yes. And they could remove the fan part of the fin. Normally they'd also go after the tail. Some people say it's territorial but goldfish don't really have territories. And if it was, why only when new fish are added. Territorial fish generally stay on the job. I think it's more of a new thing in the pond and the other fish have one of 3 responses. Can I spawn with it? Can it eat me? Can I eat it? When they figure out they can't eat it they're done.

Given good water quality, good food, etc...the fin will probably grow back. It's kind of like our fingernails, as long as the root is still there it will grow back. However it can be deformed, and/or a different color. Just depends on the injury.

If it was the other fish there is a possibility the missing fish drove into some nook to escape and got so jammed it couldn't get out. Under a rock, into a liner fold. They normally die and stay there until decay causes them to work free and float. Or never to be found at all.

 

[natbla]

Oh, the fan, not the arm...I get it now. The arm is boney and I couldn't figure out how that could be lost.

Yes, sure, larger goldfish can bite new fish. Not super common, but yes. And they could remove the fan part of the fin. Normally they'd also go after the tail. Some people say it's territorial but goldfish don't really have territories. And if it was, why only when new fish are added. Territorial fish generally stay on the job. I think it's more of a new thing in the pond and the other fish have one of 3 responses. Can I spawn with it? Can it eat me? Can I eat it? When they figure out they can't eat it they're done.

Given good water quality, good food, etc...the fin will probably grow back. It's kind of like our fingernails, as long as the root is still there it will grow back. However it can be deformed, and/or a different color. Just depends on the injury.

If it was the other fish there is a possibility the missing fish drove into some nook to escape and got so jammed it couldn't get out. Under a rock, into a liner fold. They normally die and stay there until decay causes them to work free and float. Or never to be found at all.

This morning the white fish was struggling to swim and when we returned this afternoon I found it dead floating on the surface. I think the 3 inches of rain in 1.5 hours that caused some murkiness last night may have contributed to his demise. I'm about to go do water testing to see what's what.

 

[Waterbug]

This morning the white fish was struggling to swim and when we returned this afternoon I found it dead floating on the surface. I think the 3 inches of rain in 1.5 hours that caused some murkiness last night may have contributed to his demise. I'm about to go do water testing to see what's what.

Good idea on the testing.

The killers of fish are mostly clear. Murkiness isn't generally a killer.

When you do test water you should do a test as early in the morning as possible and again in late afternoon or early evening. Repeat for several days. A single reading only tells you a little bit.