Backyard Aquaponics
A place to discuss aquaponics

Not worrying yet, but 'carp' and 'crap' are anagrams, so...

The fish are currently about 10 to 15 cm. Not too shabby.

No ammonium measurable, nitrites still on the high side, somewhere between 1-5. Nitrates around 50.

Threw in a pinch of general pond fish food (just to see if they would take it. I will use it to supplement their diet of greens) and that was completely gone after an hour or so. Though they won't come up to feed when I am there, the cowards

Question: By the way, if they are moving their mouths when hanging still in the water, does that always mean they have too little oxigen? They are staying near the bottom of the tank, not at the surface.

I have carp (brown goldfish) in my system and they like the BYAP fish feed.

Having a well balanced feed helps the plants get enough nutrients apparently?

The grass carp apperantly are fairly strict vegetarians, where most other carp are omnivorous. But I've read on the internet of people successfully feeding them with a generic pond fish food. So I bought a small bucket of premium food (had more vitamins etc per kg than the cheap food, I checked). I hope to feed them mainly on vegetable matter, but add a bit of this food to make sure that they get all they need. Also handy in winter when fresh veg matter is not as easy to come by. They'll probably eat less, but it is easier to have something ready made on hand.

I'll add seaweed extract to the water directly if the plants need it and try to feed the fish appropriately.

I've put weed supressing plastic around the tank to stop the weeds growing out of the sides of the IBC block the light a bit and prevent our shadows from falling on the tank whenever we pass. The poor dears are still very stressed out.

I've been running the pump continuously for a few hours now and, lo and behold, the FT floor is swept clean. The SLO works after all, it just needs a bit more time to get the job done than 15 mins. I'll program my timer for a slot where the pump runs coninuously for a couple of hours once every 24 hrs.

Tomorrow I'll get an air pump and stone for in the FT. We're in for another few days of 34 C and I worry about oxigen. Better safe than sorry.

34 c wow that's a hot day down here in oz.

Thats a winters day in Kalgoorlie

I know, for many people those temps aren't anything special. But for us it is pretty extreme and we are not set up for it. No shade cloth for the greenhouse etc. Because years may pass that we don't see those temperatures.

We laugh when a mediterranean country gets all fussy about a bit of snow and all traffic stops, but for them that is extreme and they are not set up for it.

I don't have any experience with carp other than goldfish but I do have experience with channel catfish that I will often call scardy cats. The tiny fingerlings are often so hungry that it overrides their natural timidity and tendency to hide and I could probably stand there at the tank with my hands in the water as they come up and feed around me but the bigger fish are normally a bit more cautious and will wait till people go away before they eat up the food. Trick is sometimes to have a little spot where you can put the food in and then have another spot you can set your victim up to peak under the tank cover so the fish don't realize people are there, (have to be quite while setting this up) I can usually get my victim splashed in the face with fish water.

There may be some good algae based feeds that would be fairly complete for your grass carp and also do well providing nutrients for your plants. I know here in FL I can order flake feed or gel feed that is algae based. It might also be possible for you to grow your own spirlulina and dry it for use as fish feed (or even a dietary supplement for yourself.) Growing spirlulina would require an aquarium size set up and mixing up something of a hydroponic nutrient to feed it but it would likely be a more complete feed and take up less space than say growing duckweed for your fish.