Will smaller fish typically mimic similar fish to fit in??? Specifically silver dollars???

So I’m putting together a mixed shoal of silver dollars… started with regular, and they are the big boys now, at about 4 inches… next available to me were some tigers, but by the time I could order, I only got 1…that one is just slightly smaller than the regulars, coincidentally or not the tiger striping was pretty faded, now is quite vivid, could be fish has grown, or there are several in there now, or a combination???... then some more became available, and I got 3 more tigers they are pretty small, in the 1.5 inch range, have vivid striping even though small, maybe because of the bigger tiger in the tank??? … then this week some spotted ones became available… I bought bought 3… out of the bag, they had no markings, from the stress of being in the bag… 3 hours later, they all have tiger stripes… there is a little size difference, the new ones are slightly smaller, being the smallest in the tank... so I know which ones are the new ones… they were bought from one of the better mail order fish sellers… so did the spotted ones blend in, or did I get miss marked tigers??? I posed the question to the seller, just in case the rest of his are looking like tigers, not heard back from him yet...

no one has witnessed this??? it looks like I now have a pack of small Tigers, even though half of them are supposed to be spotted

seller just responded, he doesn't think the spotted would mimic tigers, said most likely the pickers picked the wrong fish... said send him pictures & he'll take care of it... he does have both in stock...

It just seems that he send you the wrong ones. Spotted barbs won't mimic the tiger pattern.

Agree with the notion that spotted ones don't mimic the tiger pattern.
Referring to the overall group of silver dollars (SDs) of the genus Metynnis, common names are generally "regular", "spotted", or "tiger". There are others, but less common or less well known.
However, because there are quite a few species (14 spp recognized in just the genus Metynnis), and several of them fall in the general terms regular, and spotted dollars, it is very important to try to be more specific about what dollars we refer to, and critically important, to show pictures so that we can agree on what we are talking about and we can objectively discuss them and learn together about SD diversity.
I ask that if you could, please show pictures of your various fish.
One more important aspect is that in addition to differences among different species, individual fish can look dramatically different depending on their mood (showing or not display colors when 'horny'), as well as thorough their development as they grow. Specifically, some specimens can show stripes only at certain times, somewhat resembling true "tiger dollars", and others can show more or less spotting at various times. Thus, other characters (more stable) must be used for species level id's.
Some of my SD fish. I have currently 4 different species in two tanks (3 in one, a single species in the other).
Below, "tiger" SDs in Nov 2021 shortly after I acquired the 4 fish at ~2". They were 'children' then, not yet sexually differentiated. I kept them in a planted 75g tank for about a year.

Below, the same 4 fish in May 2023 in a 'project' planted 125 tank. Gender differences started to noticeable in 2022. The group consists of 3 males and one female (upper fish, red fin)

Below, the same fish last week. They are now young adults, ~3.5", the female (center) being largest, ~4".

Below, Also last week, the female and one of the males, showing off.

Below, The other tank, with 3 species

Below, Detail of some fish: Male maculatus at center;

Below, One of the other fish, M. altidorsalis showing off at a different date. This is the same fish as that on the upper right above the large spot fish (lippincotianus) in the previous picture. He looks completely different.

Below, spotten (lippincotianus) showing off

Please share your fish......

Well you are obviously the one this thread was written for… I need to get a picture for the seller… so some pictures coming soon

This is a hard tank to get good pictures… there is a jungle of plants growing out of it, and it’s only visible from my work area, which is only about 2.5 feet wide, so I can’t back up much… I’ll do my best…

I would have to net the fish up against the front of the tank, in order to get a good enough picture to identify the species the 1st picture is my bigger tiger…the 2nd picture is the 2 new fish

I’m getting a new cell phone next week… this one is older and has issues… will try for some better with the new phone

Nice! Theose are definitely "tiger" SDs, Metynnis fasciatus. They seem quite young. Better pictures may help, but probably gender differences are not yet clearly shown or at all. Usually, females would have a more red anal fin (than males) from fairly early, but the gender differences in shape of the anal fin don't develop until later. Also, in males, the red humeral spot only comes later in development, whereas the two black humeral spots are visible in both males and females (more in males) from relatively early.
If I understood correctly you have at least one 'regular', and one (several?) 'spotted'. Those would be nice to see as in those groups is where the most taxonomic confusion exists at the level of hobbyists. No rush, just when you can. Cheers!

I have 3 larger 4 inchish regular, & so far no spotted, still trying... I may remove one or two of my regular ones, as one has a pretty big streak on it's side... doesn't look like a growth really, maybe a bacterial??? now that my quarantine / hospital tanks are up and running I'll probably pull it out... was hoping that was an injury, & just mucus covered ( may still be ) they can be a little flighty when you don't have enough of them, & it at one time was in just a group of 3, while I tried to get more, with availability, that's taken longer than I had hoped... also the smallest of the regulars, has a "chip on his shoulder", had it since I received it, not sure if it's a growth, or an old wound, at 1st I thought it might be a fungus ( looks different than the other, as this "spot" is lighter, & doesn't look as "slimy" as the others issue, but it seems to only grow as the fish does, & doesn't impair it at all

these guys are in with a 12" Bichir, & I'm starting to think, in the future anything smaller than what I got this time, is going to have to go into a grow out tank... I was thinking, that maybe the Bichir jumped at one of the feeders I use, and startled the bigger SD, and he got a wound on the side??? Bichir works himself down into the substrate for camouflage, then pounces, at feeders

I've not heard from the seller yet, but last communication, sounded like they would send me some spotted SD if he thought the pickers grabbed the wrong fish???

we'll see how my new phone handles pictures... if there is not a great improvement there, I'll have to net trap them against the front of the tank, to get good pictures of each... I really appreciate all the info... I really had no idea on sexing them... & not really interested in breeding anything at this time, but it's always nice to know what you've got...