Is "tropical fish food" safe for ducklings? (algae wafers, flakes, bloodworm and daphnia)

[Acceber123321]

As the title really - I've got 2 mallard ducklings (caught but uninjured by a cat) - they will be being released when they're ready (had them 2 weeks now).
They're on a chick crumb as their main feed with treats like frozen peas, herbs, a few calci worms, porridge oats every few days.

Is something like https://www.amazon.co.uk/gp/product/B07DT7C6WW/ref=ewc_pr_img_1?smid=A2FGB3SRAWZEAP&psc=1 safe for them? I was toying with the bloodworm/daphnia you can buy frozen and putting it in their water, but this multi pack also have algae wafers and fish flakes. Is that safe for ducklings to have? I'm thinking the flakes would be good in their water tray as enrichment as well as feed (they love peas in their water) because I'm keen for them to remain "wild" and look for their own food, not get too used to me etc.
They're not able to be let outside (have dogs and cats) so I'm trying to give them natural things inside so they can still keep their foraging skills.

 

[Miss Lydia]

If your feeding them then your going to be hard-pressed to let them go without supporting them until they migrate. And keeping them safe from your other animals. Is there a pond close to you where the mama duck may be with the rest of her ducklings?
Whatever you feed them they need chick grit to help them grind it up. Their chick crub is the only thing they can eat that doesn't require grit.

 

[Acceber123321]

They're in a puppy crate in a spare room currently so they're aware from the other pets.
They came from a friend who lives near a river (her cat caught them and brought them back home so she didn't see mummy duck or the other ducklings) so they'll either go back there or to a lake or river near me where there are other ducks.
They do have chick grit in a tray - never seen them go near it, but it's there for them.

 

[BelovedBirds]

They're in a puppy crate in a spare room currently so they're aware from the other pets.
They came from a friend who lives near a river (her cat caught them and brought them back home so she didn't see mummy duck or the other ducklings) so they'll either go back there or to a lake or river near me where there are other ducks.
They do have chick grit in a tray - never seen them go near it, but it's there for them.

Do you have a wildlife rehabber nearby that you can contact? Or a rescue centre that deals with wildlife?

 

[Miss Lydia]

You could try these that you want to order since ducks in the wild don't eat chick crub lol

They eat a variety of plants and insects.