Q:

Powering Waterpump Low Voltage Water Pump from Arduino Micro 5 Volt pin

I'm thinking about powering 3 Low Voltage 5 Volt submersible pump consecutively with an Arduino micro. 
Those cheap pumps draw 100-200mA and the 5 Volt Pin from the Arduino Micro can supply that (i think). 
I'm not thinking about powering all pumps at the same time .. only one at a time. 
When using those 3 Pumps together with 3 Mosfets to consecutively trigger this 3 pumps, are there any problems to except for the arduino or should I go with an external power supply? 

A:

USB 2.0 and below specification only supplies a total of 500mA. Worst case on your pump estimate is 600mA so you should go with an external power supply.