even though he's tiny, the last cricket he ate was how many days ago? so start counting from there as far as updating the fact of : When is the LAST time he's eaten anything. Now after eating his cricket, he was WAS fed, so don't look at it like "My Aro hasn't eaten in over a week" it's "my aro hasn't eaten in (what 2 days?) So, he's doing OK. Just OK. Now, At this point and finding out his size, get him to eat anything he will, you've heard it all. Remember though, 10 mins, a refusal of interest, remove food and wait about 5-6 hours and try again. If you go 8 hrs, it might even work faster.
With all of this food being put in your tank, you need to check parameters daily, hecan't handle ammonia and high nit., if they're off, that could be an indicator. If my Aro doesn't want to eat, I know it's for a reason. With a baby, limit chemicals, do small water changes and keep it mellow. Measure he temp of the tank to start, use you thermometer so the end goal is the tank water stays the same, dropping or raising temp quickly even a couple degrees can really be hard on a baby.
What temp. do you have him set at? I keep mine at 81.7, that leaves a little room both ways, but I can do a water change now and never lose more that 4/10 of the starting temp.
When feeding the baby, I'd remove obstacles, plants, and even turn off bubbles or current for 10 minutes so he can fins and see his food. Light helps too!