Your dream is full of fertility symbols. Unless your dream is literal (i.e., you have pet fish), fertility is on your mind. Here are links to their definitions on this website:
aquarium (variation of a fish bowl):
dreamdoctor.com/component/dreams/?contro...y&task=details&id=75
fish:
dreamdoctor.com/component/dreams/?contro...&task=details&id=812
blood/bloody water:
dreamdoctor.com/component/dreams/?contro...&task=details&id=213
How did you feel IN your dream? Feelings in dreams are never disguised so how you felt in your dream is how you feel about the subject of your dream in waking life.
This dream reflects your feelings about having children. The "dead" fish in your dream which you revive could be symbolic of a concern that you might not be able to have children... perhaps revived (symbolically) by a new romantic attraction. The bloody water could be symbolic of your menstrual cycle or it could reflect pain in a past romantic relationship... water (a symbol for emotions) that you want to clean so that your child will be born in "fresh" water.
Your dream is informed by your waking life background at the time you had the dream. Not knowing that makes it difficult to say exactly what triggered it, but the numerous fertility symbols all point to a desire for and/or concern about having children.
Please share what was going on in your waking life at the time you had the dream so we can help you understand it better.
In the meantime, I hope this has been helpful!