Adding larger Dwarf Neon Rainbows to existing young group

[Zoeeannee]

So I think I know the answer to this question but here goes…

I bought 7 Dwarf Neon Rainbows 2 days ago (9th Jan, it’s now 11th Jan). They are really small, about 2cm each and some very thin, presumably underfed from the FS. I’m considering getting some additional larger (not necessarily fully grown) Dwarf Neon Rainbows with the thinking being that some stronger fish will help establish a strong school in the hopes that it will make the smaller ones feel safer and thus grow quicker and avoid any death from stress etc.

However, my concern here (and why I think I know the answer) is that if I got older Dwarf Neon Rainbows, they would school with the younger ones but out compete them for food. Would this be the case??

2 things for context -

Tank size and tank mates
- 300L heavily planted but still lots of open space
- cardinals
- Otos
- sterbai and peppered corys
- 2 red honey gouramis
- 1 very shy bristlenose

The story as to why I even bought the small struggling Dwarf Neon Rainbows for anyone who’s interested -
I got them from Pets at Home (UK pet store chain) I have only ever bought fish from pets at home once before and have since vowed to never buy from there again because I think they keep them in poor conditions and also have low quality stock… however I was in there just to get some fish food, and by chance saw the rainbows and thought “omg they’re far too small and will inevitably be sold to someone who doesn’t have an adequate tank for them, I need to take them”. So I took them and here we are

 

[MuddyWaters]

This is probably not a great answer, but I don't have a problem with fish getting out-competed for food because I overfeed them anyway. I tend to change water a lot more just to compensate, and I will go a couple of days with nothing every now and then, but my opinion is that if you were to overfeed for a few days to get these new fishies some meat on their bones, it's not going to hurt anything, as long as you change the water and have healthy filtration.

Edit: Not that I'm recommending overfeeding- it's a bad habit. I'm just a sucker for begging fish.

 

[Zoeeannee]

This is probably not a great answer, but I don't have a problem with fish getting out-competed for food because I overfeed them anyway. I tend to change water a lot more just to compensate, and I will go a couple of days with nothing every now and then, but my opinion is that if you were to overfeed for a few days to get these new fishies some meat on their bones, it's not going to hurt anything, as long as you change the water and have healthy filtration.

Edit: Not that I'm recommending overfeeding- it's a bad habit. I'm just a sucker for begging fish.

I am currently over feeding (and doing a s_*T load of water changes and partial filter cleans to compensate) so that the, as you so eloquently put it (lol), “fishies get some meat on their bones” but I’m just wondering if as well as feeding them, whether older fish of the same species would help or hinder their growth

 

[GaryE]

I would proceed cautiously. First, you need to determine why they are thin.

We all take pity on struggling little fish, but buying them without a quarantine tank has a way of backfiring. This is especially true with box store praecox, which are often ill. Adding bigger rainbows might just be putting them at risk.

I would have isolated them for at least 3 months, in their own tank. Unless the fish you buy looks wonderfully healthy, you are taking a big risk buying it. You have to see if they can gain weight with normal feeding, or if they have a wasting disease. Most people don't have QT tanks and buying the healthiest looking fish they can find from the best sources is the only line of defence. Rescuing sickly fish has caused many a tank wipeout.

Heavy feeding is probably not how to proceed. M praecox like their food and don't have to be coaxed. They are slow growers in terms of length, but they should present a full, healthy body weight pretty quickly of their problem was just neglect. Watch for bent spines, sores and an inability to put on healthy muscle.