First things first the picture was rotated ,
Fish grow to the volume of water within the tank, the aquatic shop didn't have a problem. And the tank is bigger than 25 gallons.
water volume has nothing to do with fish size , salt water fish don't fall into that fresh water fantasy , weather your fish is in a 5 g bucket or a 100 gal
tank they will grow at the same rate . it has absolutely nothing to do with the amount of water or tank size .
saltwater fish and tank size recommendations are put in place due to the rapid growth of the fish and to prepare you for the overall out come .
the fish store you bought them from shows they are just in it for profit , not caring for the overall health of the fish . they want you to spend money , the salt water hobby is not cheap in no means and to have a shop mislead you telling you things you want to hear in order to get you to spend spend spend .
I'm not telling you this because I'm making a profit because I'm not . but because way to many new comers are mislead . shop owners see the glow in your eye seeing you are new to the hobby and will try to sell you as much as they can . if your stock dies the next day do they compensate you no . why they already got your money and just frankly don't care .