How i come to know about fish pregnancy and get ready if they are?

Hi. I bought a fish aquarium in october.(wen winter starts).
Now it is May(summer starts).
I have 7 kissy fish( calm fishes) and 3 KARP(medium fast).
Do fishes breed in summer? They lay eggs or simply deliver nourished one? Do filter catch eggs? How to come to know if a fish is pregnant? If she is how to care for her? Oh GOD i know nothing , please help me out
Answers:
Here's some good info about your kissing fish:

http://freshaquarium.about.com/cs/anaban...

By Karp I assume you mean koi. Here;s some ingo about them:

http://www.olympickoiclub.org/koicare/br...

Hope that helps

MM