I put 9 rosy red minnows into my raised pond two months ago. Looking at the pond just a minute ago, I saw about 50-100 small fish! If they all grow to full size, I don't think my pond (1500 litres) will be able to support them. I am not sure what to do now. Do I simply let the amount of available food in the pond regulate the numbers or is it better to remove some fish now? To be honest, both options are not very nice, so I would be very grateful for some advice. Going forward, I assume it would be good to always check for fish eggs?

Not sure what to suggest, although it's possible some will be eaten by the adults.

Thanks! I think I will just observe what happens.

Depending on how things turn out with your observations, you may also wish to give away / sell some via https://www.aquarist-classifieds.co.uk/php/recent.php