How do I gelatin?

[ichthyogeek]

A lot of DIY fish foods call for "preparing gelatin like it says on the packet." Except those either ask you to bloom the gelatin, and then pour boiling hot water onto it to redissolve it, or just have you dissolve the gelatin into the boiling hot water directly. And then pour the gelatin-y water onto the food.

Am I missing a key concept here? I thought I wasn't supposed to cook the food? But I'm boiling hot gelatin paste onto it?

 

[Jay Hemdal Verified Community Expert]

Coincidentally, I'm just finishing up on a medicated food article for R2R. Here is the recipe I have, I also list a process for spray drying meds onto food with a solvent. The seafood ingredients can be tweaked, you just want to keep the food/water/gelatine ratio about the same. It keeps the food from being denatured by heat, but the result is a bit lumpy. I'd make a partial batch and experiment with it first....

Recipe for general formula gelatin fish food

To make 1 kilogram (2.2 pounds) of food:

1) Dissolve 3 ounces, (3 packets) of unflavored gelatin in 300 ml of very hot water (160 degrees F.)

2) Blend together the following ingredients:

100 grams of smelt or other white fish flesh

50 g frozen mixed vegetables (or 20 grams of dried Nori algae for marine fish)

50 g shrimp tails, peeled

100 g small krill or mysid shrimp

30 g flake fish food, freeze dried foods, etc.

2 g Spirulina powder (optional)

1000 mg ascorbic acid (optional)

1 multi-vitamin tablet, crushed

300 ml water

3) Once the gelatin has cooled to 110 F., fold the dissolved gelatin into the above mixture,

4) Fold in any additives, such as medications. Blend for 30 more seconds at low speed.

5) Pour mixture into ice cube trays. Place the trays into the freezer.

6) After about one hour, remove and cut each slightly hardened block in half, leaving the two pieces inside the tray.

7) Return to freezer for 6 or more hours. Remove blocks, and separate at the cut points. Return blocks to freezer for storage. The final product should probably not be kept longer than two months.

8) Mazuri, a subsidiary of Purina offers a line of powdered gelatin food pre-mixes to public aquariums. Different formulations are available (such as herbivore and carnivore varieties) and it is easy to add supplements to the mix such as HUFAs or vitamins. These mixes are much more convenient than making your own food from scratch, and they have had the obvious benefit of having been formulated by nutritional experts.


Solvent spray dosing

If a particular drug can be dissolved in a solvent, that solution can then be sprayed onto a flake, freeze-dried or pellet food with good assurance that the drug will soak in and bind with the food when allowed to dry. Pure ethanol is a common solvent. In some cases, distilled water can be used. Simply calculate the amount of drug to be added to the food item and dissolve it in the least amount of solvent as possible. Spread the food item out of a tray and spray evenly with the solvent/drug mixture and allow to dry.

 

[BackToTheReef]

A lot of DIY fish foods call for "preparing gelatin like it says on the packet." Except those either ask you to bloom the gelatin, and then pour boiling hot water onto it to redissolve it, or just have you dissolve the gelatin into the boiling hot water directly. And then pour the gelatin-y water onto the food.

Am I missing a key concept here? I thought I wasn't supposed to cook the food? But I'm boiling hot gelatin paste onto it?

Do you really need the gelatin though?

 

[GlassMunky]

Why use gelatin at all?


my fish HATE food that’s geled up

I’d stick to just frozen if I were you

 

[Jay Hemdal Verified Community Expert]

Why use gelatin at all?


my fish HATE food that’s geled up

I’d stick to just frozen if I were you

The recipe I posted is as a vehicle for medication, so you need the gelatin as a binder. The trick is to go with the least amount of gelatin as you can, and fish typically have to be accustomed to it over time.

Jay

 

[GlassMunky]

The recipe I posted is as a vehicle for medication, so you need the gelatin as a binder. The trick is to go with the least amount of gelatin as you can, and fish typically have to be accustomed to it over time.

Jay

I didn’t see medication listed...
But just curious why you need the gelatin? Does the medication not just soak into the foods like any other additive like vitamins?

 

[DaneGer21]

Here’s what I do.

I go to the local fish/seafood store. I buy a few clams, scallops, shrimp, oysters, and I ask for a few fish scraps. This is all 100% fresh on ice. I take it home and throw everything in my magic bullet. I also toss in so brine shrimp, mysis, and fish eggs. I blend it up for just seconds, then add a few dry foods, flake, pellets, reef chili, reef roids, etc. I blend it for a few more seconds and it’s done. Put a piece of wax paper down and set a small piece of eggcrate on top. Spread the seafood sludge into/onto the eggcrate. Place in freezer.

Remove individual cubes as you wish and toss into the tank, or thaw in tank water and dump in.


Add medications, selcon, garlic, whatever as you wish.

 

[Jay Hemdal Verified Community Expert]

I didn’t see medication listed...
But just curious why you need the gelatin? Does the medication not just soak into the foods like any other additive like vitamins?

The medications are added from a formulary that is in the article itself, I just posted the gel recipe. I'm working on getting the whole article posted here. This is why soaking foods in medications cannot work:

Presently, many aquarists try to soak their fish food in medication and then feed that to their fish. The trouble is that this can never really work. Oral fish medications are always dosed on an “as fed basis”, usually milligrams of medication per kilogram of fish biomass. In the case of soaking food in medication; the amount of medication per gram of food is unknown, as is the weight of the fish, and so is the amount of food being fed. With that many uncontrolled variables, a proper dose simply cannot be formulated.


Jay

 

[GlassMunky]

The medications are added from a formulary that is in the article itself, I just posted the gel recipe. I'm working on getting the whole article posted here. This is why soaking foods in medications cannot work:

Presently, many aquarists try to soak their fish food in medication and then feed that to their fish. The trouble is that this can never really work. Oral fish medications are always dosed on an “as fed basis”, usually milligrams of medication per kilogram of fish biomass. In the case of soaking food in medication; the amount of medication per gram of food is unknown, as is the weight of the fish, and so is the amount of food being fed. With that many uncontrolled variables, a proper dose simply cannot be formulated.


Jay

Even with the gel though I fail to see how you’re getting a “proper controlled dose”
Because as you mentioned you have no idea how much the fish weighs so even if you know how much medication is in the food that’s only half the issue.
mans then even if you do know the weight of the fish and the dose of medication In the food how can you control how much they eat.

i guess I just don’t see what you’re getting at and why the extra work is needed.

 

[ichthyogeek]

Wait until you see the gel models of fish Jay has GlassMunky....

Mostly, I'm concerned about blitzing the frozen food into oblivion, and when it melts, it'll essentially be particulates that the fish won't acknowledge as food. Adding gelatin would be ideal because it will essentially bind everything together for the fish to eat in small enough pieces once crumbled.

I could grate the seafood by hand, and have done so in the past, but it's going to get very old, very quickly once I start doing it every week. The middle-sized holes in box graters are perfect for the particle size I want, but I dislike having to wash box graters, accidentally grating my knuckles, and spending an hour on grating frozen seafood for a week's supply at a time...maybe I should figure out how to DIY a food processor add-on that will grate the food for me...

 

[BackToTheReef]

Wait until you see the gel models of fish Jay has GlassMunky....

Mostly, I'm concerned about blitzing the frozen food into oblivion, and when it melts, it'll essentially be particulates that the fish won't acknowledge as food. Adding gelatin would be ideal because it will essentially bind everything together for the fish to eat in small enough pieces once crumbled.

I could grate the seafood by hand, and have done so in the past, but it's going to get very old, very quickly once I start doing it every week. The middle-sized holes in box graters are perfect for the particle size I want, but I dislike having to wash box graters, accidentally grating my knuckles, and spending an hour on grating frozen seafood for a week's supply at a time...maybe I should figure out how to DIY a food processor add-on that will grate the food for me...

they already make grater blades for them.

 

[ichthyogeek]

they already make grater blades for them.

Wait they do? And for tiny food processors (<4 cups)? My mom's got one of those giant food processors (~14 cups), which came with absolutely everything, and while the grater attachment is grate(pun intended) for making papaya pickles...for making a tiny batch of food, that's just not okay for me, since I'd have to assemble, clean, disinfect, clean again, and otherwise sterilize the thing due to my food allergies.

 

[BackToTheReef]

Wait they do? And for tiny food processors (<4 cups)? My mom's got one of those giant food processors (~14 cups), which came with absolutely everything, and while the grater attachment is grate(pun intended) for making papaya pickles...for making a tiny batch of food, that's just not okay for me, since I'd have to assemble, clean, disinfect, clean again, and otherwise sterilize the thing due to my food allergies.

YEs but I am sure it is brand/model dependent. Even the cheaper larger versions come with them now. Instead of blades it looks like a box grater but in a circle. I tried to find a pic of just the blade but here is like to an example...


Edit: Also this


Now personally I'd find a cheap food processor that comes with one b/c I don't want to "stink up" a good one.

 

[ichthyogeek]

Thanks! Now I have even more stuff that I can prepare to buy with my non-existent money from my non-existent job to deliver to my non-existent apartment haha!

 

[BackToTheReef]

Thanks! Now I have even more stuff that I can prepare to buy with my non-existent money from my non-existent job to deliver to my non-existent apartment haha!

I am in that boat in about 45 days pending any miracles.

I'd check wally world or tarje for a cheaper cuisinart and see if they come with the grater blade. Some times you can catch them for like $20-$30 and I just got a $5 coupon at tarje for getting a flu shot.

 

[Jay Hemdal Verified Community Expert]

Even with the gel though I fail to see how you’re getting a “proper controlled dose”
Because as you mentioned you have no idea how much the fish weighs so even if you know how much medication is in the food that’s only half the issue.
mans then even if you do know the weight of the fish and the dose of medication In the food how can you control how much they eat.

i guess I just don’t see what you’re getting at and why the extra work is needed.

The process I developed has a database and images used to estimate how much your fish weigh. When I get it all loaded up as an article, please take a look at it. Yes, the process is complicated, but is really the only way that you can effectively dose oral meds.

Here is a case history:

Case history:

An aquarium housing 13 rather small fish needed to be treated with oral antibiotics. The veterinary recommendation was to use erythromycin, dosed at 100 mg/kg fish body weight in the diet for 14-21 days.

The first step was to estimate the fish mass in the aquarium (in this case, comparing to a known weight data set). 10 platies (about 5 g total) 1 goldfish at around 40 g, one or 2 danios at 2 g and one large tetra and 10 g, for a total mass of around 57 grams.

For the erythromycin dose, that works out to be 5.7 mg of erythromycin fed to the whole tank each day.

One usually assumes that the fish will eat around 3% of their body mass each day, so for this system, that works out to be 1.7 grams of food per day. Therefore, we need 5.7 mg in 1.7 grams of food, or 670 mg in 200 grams of medicated food.

Erythromycin is soluble in ethanol. Dissolving 670 mg of erythromycin in the smallest amount of ethanol possible and then spray it on to 200 grams of flake food and allow it to evaporate. The fish were then fed 1.7 grams of food daily (spread over three feedings).

Jay

 

[ichthyogeek]

Note to self...in case of sick fish, get them drunk....preferably using vodka....