Backyard Aquaponics
A place to discuss aquaponics

Well, I never managed to get my big system above 76degF(24degC) all summer, even when the air hit over 100degF(38degC). The tilapia never really ate well and finally succumbed to something while I was away. To heck with them unless I make a more complex system that manages heat loss and gain a lot better.

New plan: since the dewpoint around here is about 55degF(13degC) in summer I hope I can keep trout happy if I just remove my small solar heater (a glass panel over the tank) and replace it with an aerating fountain (and fan, as needed). I've found a source of channel catfish and rainbow trout and plan to get about 150 3"(8cm) fish on Tuesday.

Right now, I have three goldfish, three tilapia, and three nice catfish. I'll eat the tilapia before they die at low temps and am not worried about the goldfish hurting anything, but the cats are up near 16"(say 40cm) and will probably enjoy trout fingerlings...as snacks.

SO, should I put the new fish in a blue barrel beside the big tank and pump water through until they are larger or eat the cats or what? Will large cats eat small cats?

I wish I knew if there were residual chemicals in the swimming pool so I could link it into the system pro tem..... Now THAT would be fun! Perhaps I should drain and fill it for the new fish...

It really depends on your goals for
the larger catfish. I would start
fresh with the fingerlings by cleaning all the big fish out of the tank. 16" catfish can and will eat some 3" fingerlings.
Also, you take a risk of exposing new fish to diseases from big fish or vice versa.
Not likely but possible. Also, the bigger fish will be more difficult to harvest without damaging the smaller fish later. I don't recall the size of your tank but You could use a hapa style net to isolate one
size from the other.

I would just eat the catfish and give the goldfish away. Or drop the goldies in the pool, your not going to eat them unless you really must.

Very reasonable, esp since I had unexplained tilapia deaths up until a month ago...

My Well fed catfish didn't seem all that interested in eating baby tilapia. I had quite the challenge catching the escaped tilapia and small tilapia out of my big in ground sump. I had hoped the huge catfish would eat the small tilapia but no.........
Anyway, probably best to follow the previously given advice though.

I do like using Hapas, or cages to keep different fish separate but there is a bit of a challenge with feeding and such cages, the food tends to float in or out of the cage and this can make feeding the appropriate amount to the appropriate fish tricky.
However, it can be quite impossible to catch the fish that is not in a cage since the cage gets in the way and the fish can hide under/around it.

TcLynx,

How did you construct your happas? Where did you get appropriate netting?

I just got a roll of netting from Aquatic Eco Systems and used PVC fittings and 1/2" PVC to make the frame. Then we just zip tied the netting to the frame and I hooked the frame up in the tank so it wouldn't sink down. Not really very scientific but it seems to have worked ok for my situation.

Sounds good. I need to order more uniseals anyway.

Well, time to present results to date:

In order to separate the trout from catfish I set up a couple blue barrels and diverted part of the growbed water into the first, through SLO into the second, through SLO into the main FT. Worked well, fish grew to about 6inches (15cm) by Feb 1. In that entire period I found no dead trout. On transfer day I found one with a lost tail fin (which I quickly offed), and two that had grown only a bit and seemed unhealthy (also offed).

Note: the big tank with the catfish is nearly non-inspectable: it has a 5 meter (16') length that is covered with growbed and is thus a pitch dark cave. The catfish love it, but it requires flashlight, mask, snorkel, and (in winter) a wetsuit to check there.

After transfer all fish seemed fine and happy and the goldfish seemed to enjoy the company. After nearly a week I found a trout backbone. Since then I've found the remains of a trout every day or so, usually with head gone (rotted off?).

So,
Trout are still hungry and celebrate mealtime.
Salting does not help and neither does water change.
Deaths started immediately after moving the fish.

I'm guessing that either
1) fish were injured in transfer
2) the fish are injuring themselves in new tank
3) the lack of current in larger tank is a problem
4) a catfish is biting their heads (possibly in retaliation of whisker nipping)
My money is on #4. Maybe that was the reason for last October's "HSM: dying fish 3300 miles away" with my tilapia dying in the same tank.


Important lessons:

1) catfish will bite smaller fish,

2) never, NEVER, NEVER make a rectangular tank under a growbed. It may be great for stable temps, but really lousy for fish health and catching fish.


So......I guess I need to set up a side tank for the catfish and buy a net to catch them. This is unfortunate as I really like having the cats in there to clean up excess food if there is any.

And I need to get or build another tank to replace this one. DANG.

Let's see: a large round tank for trout, running through SLO to another tank for catfish cleanup crew, running to growbeds.

if you plan to eat the cats you could fish them out.

That's the plan, but (due to complex considerations) would like to wait for a sunny Saturday to pull them out and have a fish tasting (first AP catfish ).

And I still need to go in after them as I have no way to get them to come to me. If I glimpse one of them once a month I'm lucky.



HEY! Tomorrow may be sunny!

Weather did not cooperate, but I did set up a side tank to isolate the cats and went in after them. This is the first time I've caught them without a net: strong buggers! Now we will see how many trout corpses show up in the next week...

Hey that looks like fun.........

So how are you going to cook it...?

Yeah, if I had those catfish, a bayou, and some collard greens there's be a big Southern party on here on the weekend.

Those are two of my three big cats. I'm planning to invite anyone over who has a recipe for catfish or an interest in AP and we'll do a taste test: poached, fried, grilled, etc.

I wonder if there is a good recipe that includes beer? It would be appropriate as I caught these three as fingerlings living in sunken beer cans I removed from a local lake about 1.5 years ago.