I do not keep reptiles and have no interest in doing so, But I have kept a lot of fish over the past 25 years including breeding a number of them. I did try doing some live foods many years ago. When my DD black angels spawned and I tried to raise the fry (I had over 100 eggs per spawn) I had to hatch BBS for them. I had to hatch them in a gallon mason jar in my the bathroom next to a 10 gal grow tank for BN.
This used to coat the tank glass next to the jar with salt. The bubbles coming out of the jar wout hoit the glass then the water evaporate leaving the salt behind. I used to get frozen Cyclop-eeze back then and would beging mixing it in with the BBS after the first week. By the end of week 2 the fry were eating 100% cyclops. The fish were giving me 100+ eggs every 2 weeks and I realized I did not want to breed angels.
Live Blackworms were one of the preferred live foods for conditioning the Hypancistrus plecos I began working with not long after I gave up on the angels. But they are stinky and needed to be kept in the fridge which was not going to happen. So, instead I began trying red wigglers worms which I would buy online and get mailed to me. These were easy, or soI thought. I kept them in a styro container with a lid and filled with damp peat.
The problem with red wigglers is that they dislike light and will stay in the peat below the surface as long as it is light above. So I tried using the lid of the styro overnight to keep them inside the box. This does not work as they are able to get out of the styro despite having the lid on it and I had my first experience with a floor full of dead worms the next morning. But the fish loved the worms and I would even cut some in half to feed to corys. A single meal of live worms and the corys would spawn withing a week.
So I got the bright Idea of getting a small goose neck desk lamp and a timer. The lamp was over the surface of the styro and the timer would turn it on before dark and off after daylight. I set the box on the hearth of the fireplace which was L shaped was in the living room and had lots of room for the box of worms This worked well until one night the power went out and so did the light. The next morning I had 100+ dried worms all over the carpet. This ended my using red wigglers.
The challenge was trying to find foods with close to the same value as live. The answer was frozen. But, I like to have a mixture of foods and also used kensfish sinking sticks. I made my own blend. And then I discovered Repashy foods, especially Spawn & Grow. I was still using the froznn Cylcop-eeze. But the only lake with them had the population crash and they were never able to get the colony re-established. Repachy foods helped a lot.
The last major dietary change I made for my fish was to switch from the kensfish food to Ebo-Aquaristik fro,=m Germany. I would buy dir3ectly from them and have the food sent to me. This worked well as the $800 exemtion from paying any fees to import things meant my few $100 order went "un-taxed." And then the president did away with that exemption and I was forced to buy the Ebo food from sources inside the states.
I have not used any live foods for almost 20 years now. The frozen and Repashy have worked very well for me as the second best option after live. For me live was one step to far for me to go. If I had not been able to succeed with my alternatives I am not sure what I would have done. While I live in a nice place, it is on the small side and despite being single I had other family members involved with living here and today my brother and I share the place. It has no basement so my tanks have been spread out and I have always been space constrained. So, live foods we not a viable option especially if they need to be in the shared fridge.
What I can say is that the foods I have been feeding for many years have worked pretty well. I consider diet to be one of the most important things we control in terms of caring for fish. I cannot speak to the reptile issues. But i can say breeding plecos have paid for every penny I have or do spend on keeping fish. This means all my fish not just the plecos.
However. I do know that live foods are best, but what I have is as close to live as I can get and it seems to have been close enough. But I also pay up for frozen and Repashy because it is what I need since live are just not an option. One benefit to hold the prices down a bit for the frozen is due to the fact that one of the folks who run my fish club brings a stryro full of frozen Hikari foods to every meeting and sells them to the members for a fair amount less than I would have to pay buying them online. For ex: a 1 lb slab of brine Shrimp is $8. I also buy frozen foods from Jehmco which are a bit less expensive as well. I ordered a few $100s worth twice a year.
For fry and smaller fish I now use frozen rotifers and a few frozen daphnia. I no longer do blood worms as I am quite allergic to them and even wearing latex exam gloves does not help. I really miss the Cyclo-eeze.
p.s. Imo, the difference between reptiles and fish is that fish must be fed almost daily while the reptiles do not need this. So. for them it is less work doing live.