I made two different batches, one for the goldfish and fry, the other for the plecos. Here is what went into them.

Goldfish/fry:
handfull/~1/8 cup edamamae (soy beans)
1 cup frozen peas (thawed and deshelled, no salt added)
some fresh dandelion leaves from the yard
mixed salad greens (beet greens, spinach, some sort of red cabbage, one other unknown)
6 cubes each frozen: bloodworms, brine shrimp, mixed spirunela algae/mysis/brine shrimp
1/2 navel orange (peeled out of the segments)
1/2 container baby food each: carrots, green beans, applesauce
1/4 cup pumpkin (roasted, pureed, then frozen)
spoonfull of minced garlic
1 powdered multivitamin
1 can (8 oz) low sodium v8 (to mix gelatin into)
1 packet gelatin

Pleco:
1 large cucumber
12 cubes frozen mixed spirunela algae/mysis/brine shrimp
mixed salad greens (same as above)
shells from the peas put into other gel food
1/2 container baby food each: carrots, green beans, applesauce
powdered sundried baby shrimp
1/2 navel orange
spoonfull of minced garlic
1 can low sodium v8
2 packets of gelatin

Got both made up and put into fridge before I went to work. When I got home the food for the goldies had set but the pleco one did not. So I added another 2 packets of gelatin to the pleco mixture using dechlorinated tap water and put back into fridge, will check on that one tomorrow.

Then the fun stuff...feeding the food to everyone The fry had no clue what the gel food even was, as they are used to food floating in the water or eating fom the surface. The plecos did not like the goldie mix, but the two female minnows in that tank seemed to like the food. The males were too busy showing off against each other to realize there was food at the bottom of the tank.

Then I took some upstairs to the goldfish. The two (new) golfballs in quarantine seemed to enjoy it after they figured out it was food. So I put the other piece in my 46 gal tank for the other goldfish. Pig came and ate the whole chunk in one bite when I looked away for about 2 seconds! So downstairs for more pieces and back up to the tank. Dropped all 4 pieces into the tank and spread them out a bit. The loaches immediately started tearing off chunks and knocking the gel around the bottom as they wrestled for the best spots to get a mouthful. The two fancies were a bit more timid at approaching the green blobs, but eventually caught on that they were food.

All in all, I think it was a hit.

The second batch did not set up even witht he extra gelatin Some of it boiled over in the microwave when I was heating it to get it to dissolve. Im gonna try adding another 2-3 packets today and see if that works. Only thing I can think of that might cause this batch to not set up is the cucumber has a lot of water in it...but human jello is gelatin, flavoring and just water. There was about 3 cups of food mixture before I added the first gelatin to it yesterday.

Anyone know what could be my problem with this?

My only thought is maybe the acidity of the oranges? But if the first one set up then, that shouldn't be the problem, I just know that the package of Jello says not to add certain fruits because they are too acid and will not allow the gelatin to set up.

I thought about the oranges too, but like you said the first one had set up just fine. I added another 3 packets of gelatin this morning before going over to my mom's house for easter baskets. By the time I got back the second batch had finally set up. After I'm done cleaning/setting up for the guests today I'm gonna go see if the plecos like my culinary creation.