Should i Get Silver Dollars?

[troublesum]

Quick back story i have a 6" 125 established running 8yrs+. I have 8 F1, red terror fry 6 at 2in the other 2 1.5in ive had them 2 months they are pretty skittish still plenty of hiding spots as i have 2 XL filter sponges and 2 FX6 and 2 clay pots and 4 rock caves.
I wanna get some silver dollars or red hooks i would like only 4 is that enough? i like the wide bar, the blackberry, tiger stripe. Question which one do better in only a group of 4 i'm open to other types of red hooks and regular silver dollars.
Question 2 will the fry freak out if i add the SD now or should i wait till a pair form or when they get bigger? I know i still have 8 months to a year before they mature.
BTW they get 3 70% WC per week

 

[FJB]

I can’t say anything about the possible relation/interactions of the dollars and the cichlids, particularly when the cichlids grow.
Regarding the dollars - they like to be in groups and four of them is bare minimum. How they interact among themselves depends strongly on gender composition. In larger groups (6 or more) the potential problems are less. However a 125g is not very large.
Also, you are considering widely different types of silver dollars. Wide bars (Myleus schomburgki) get the largest of those mentioned. Too large for the 125g even without the cichlids. Red hooks are second in heft, too large in my opinion. Blackberries (hybrids of two Myleus spp) are next, maxing at substantially smaller size than the either of the former. The smallest mentioned are the tigers, Metynnis fasciatus. You mentioned ‘regular dollars’ (other Metynnis species) which are similar in size to the tigers.
Due to their max size, I believe you should stay with Metynnis dollars and not consider any of the Myleus. The tank is just not large enough for a good group of those larger species, particularly with the cichlids. It is not about the filtration which sounds fine, but about space.
Others may disagree. Good luck!

 

[Jexnell]

Honestly unless you already have said dithers on hand in another tank, I wouldn't bother with dithers at this point.

If you get new fish they need six to eight weeks of quarantine before you can add them to the main tank. By then the Festae will be nearing the 3in mark, what brings sexual maturity. At this point they lose the shyness as they sort out who's male/female and possible pairings.

Quick easy way to help them now is dimming the lights and getting some cheap plastic plants to float on the waters surface. In the wild a fishes worst enemy are birds. Give them cover and they will feel safe to come out more.