Which Fish Do I Start With?
New tanks have very little stable bacteria to process wastes, even if you have added a bacterial starter, so they are prone to fluctuations in water chemistry which can be harmful to delicate species. As well as delicate fish you should also avoid:
Algae eating fish - There will not be enough established algae for them to graze on
Scavenging fish - These fish need a separate sinking food, and you should avoid using lots of different foods at the start
Heavily line-bred fish - Fish like guppies can be very weak due to inbreeding and are more likely to become ill in new tanks
Demanding species - Any fish that has special feed requirements should be avoided
So which fish should you start with? Firstly, you need to have an idea of which fish you intend to eventually keep so that you can select the best candidates from your list (see the question on 'how do I choose fish') The next step is to pick the hardiest fish, following the recommendations of your retailer, or the information on the species from this site.