The cheapest and most effective way of heating a large predatory catfish pond?

[thebiggerthebetter]

Then you have a lot less to worry about. The ground temperature usually never changes year round below 2 ft depth, which in southern Florida is around 74 F. It doesn't matter concreted or not. That's your source of geothermal heating for the colder times and cooling for the warmer times.

 

[Andyroo]

74F (23C) isn't going to be problematic to his amazonian cats?

I ask as we're installing a 5x10x5 concrete in-ground for silver arowana - we're on a mountain & stormy January nights can get down to 18C (64F), is why I ask. Air temp pops back to 22 as soon as the sun comes up, and we've kept as much depth per surface area as we could. I will tent through those nights & for the particularly chilling rain.

However, I'm also wondering about an electrical backup; thinking the guts from an old water-heater but the thermostat's likely not fit to task.

Note: the neighbour used to breed & sell angles in concrete in-ground tanks without covers nor tents & never had a temperature-related mortality (event)... just herons.

 

[thebiggerthebetter]

The lowest our 25K has down to was 68-ish F (20 C). We have quite a few tropicals in there but no Amazonian catfish.

The silver arowana died on our hands at lower temps, like 55-60 F short term. IDK how low they can handle long term.

 

[Andyroo]

The aro (and everybody) did an overnight at 20~21C in a serious cold snap in the Bay (town) 18months ago & didn't seem to skip a beat. Only the clown loaches seemed to suffer, they went very quiet until it came back to ~25. I keep a heater in that tank now. This pond will almost certainly see nights where the air (and rain?) is 64~65F, and so it's 5' deep & will get a winter tent & maybe heater if I can figure that out... 2'nd-hand hot-tub guts on Ebay

 

[thebiggerthebetter]

I am surprised the clown loaches didn't suffer an ich breakout - their "favorite pastime" it seems.

I think you'd be fine with just the tent cover for occasional cold spells of 65-ish F.

Having a heater stand by is a good insurance. A hot tub water heater would suffice but is quite electric hungry. Like you said, household water heater could work too, if you'd be the "thermostat", unless very handy with rigging electric and electronics.

 

[Isaiahm]

I am surprised the clown loaches didn't suffer an ich breakout - their "favorite pastime" it seems.

I think you'd be fine with just the tent cover for occasional cold spells of 65-ish F.

Having a heater stand by is a good insurance. A hot tub water heater would suffice but is quite electric hungry. Like you said, household water heater could work too, if you'd be the "thermostat", unless very handy with rigging electric and electronics.

i want to build a 1500 gallon pond for my hybrid retail and a few other south american cichlids and silver aro and i live in california and in the winter it gets around 40-50 f at night if i have it underground and put a tarp over it and have like a 500 wat heater or something similar do you think it’ll be able to stay warm enough

 

[fishdance]

The cheapest (to run) and most efficient way to heat a large predatory pond is a water heat pump as these have up to 16X COP. So 1kW of electrical power will produce 16kW of heat! Your pond/tank needs to be insulated regardless of how you heat, especially the top which will lose 70% of heat. Heat pumps can be expensive to buy though. I only use heat pumps on bigger tanks & ponds (over 80,000L). With a long warranty and local service support & spares. I have 4 days before the thermal mass of my tank(s) start to drop.

I run clown loaches in above ground intex swim pools with a clear plastic cover. These are 10,000L volume and I use direct heat solar panels used for swim pools to heat these. Stay away from the flimsy strip pool heating, use robust heavy duty like OKU (German brand). I estimate one panel provides 1kW heat. Slow recirculation during daylight. Turn off water at night. You can get temperature controllers to speed up or slow down pums water flow but I prefer less automation.

https://www.ecoonline.com.au/performance-oku-solar-pool-heating-system-automatic-kit/

Some suppliers will not selll these for aquaculture or pond use so you may have to purchase without warranty. (Swim pools have chlorine). The OKU brand is fantastic. I can walk over, not worry about hail storms, UV degradation etc. I use 10 panels in series on the roof of a fish shed (300+ tanks).

Another option is solar evacuated tube collectors which would work but seemed overly complex. I have plenty of strong sun where I live so this option was overkill. Easily capable of boiling water.

 

[Andyroo]

I bought one of these for the pond (~1800gal) as I'm really only worried about the few stormy winter nights that might dip to 17C or so, keeping it >21.

https://www.amazon.com/gp/product/B09DFHZ9GX/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&th=1

I've yet to hook it up as none of the control & plug fittings are water-tight... scheduled for today, can keep you posted.
To do again and/or assuming it works, I'd buy out of Europe for the 220V.

The guys on the next & higher mountain don't bother heating, just design with plenty of depth & set a tent/tarp on these nights: silver arowana, irid sharks, tinfoil, pacu, angles, af.cichlids & clown knife are what have been discussed (as tropical, vs koi)

 

[dr exum]

gas

 

[thebiggerthebetter]

i want to build a 1500 gallon pond for my hybrid retail and a few other south american cichlids and silver aro and i live in california and in the winter it gets around 40-50 f at night if i have it underground and put a tarp over it and have like a 500 wat heater or something similar do you think it’ll be able to stay warm enough

This might be enough but I can't be sure. What part of Cali? What's the ground temperature year round below 2-3ft? Are the low temps of 40-50 F regular or exceptions / cold spells?

I'd build the pond and experiment with it before populating with tropicals, if I wanted to be cautious. Until then, you can keep plenty of temperate water fish, if you have to.