Dear E M,
Oh...all the "Do Nots" of pregnancy. That seems to be a list that just keeps getting longer. Sometimes I wonder how kids were even born generations ago with all the things you aren't supposed to do nowadays. My two nieces have had 3 children each in rapid succession and I never heard about the fish tank thing. I suppose it would depend on what type of tank you have, if you would be exposed to any chemicals or fish illnesses such as "ick". (I think that's how it's spelled). Most likely, the main thing would be just to properly wash afterwards. You should ask your doctor for more information on it so you can at least understand why they ask you not to do it. I can assure you with most certainty that cleaning your fish tank once hasn't done any harm to you or your baby. I've always had birds and cleaned their cages while pregnant. That's probably on a don't list now too. Just don't stress out about it and see if you can get someone to help with the fish from now on.
I don't know if you've ever seen it, but I fell in love with the show "Mad Men" on AMC. It's about the lives of advertising executives, set in the early 1960's. Aside from being an excellent show, I was born in 1962, so I found it very interesting from that aspect as well. Pregnant women drank and smoked, no one used a seat belt, not even the kids. In one episode, the main character's wife Betty, is sitting at her table visiting with her pregnant friend. Her friend mentions that the children are playing too quietly so she calls for her little boy who announces they are playing "space man". He and Betty's daughter come around the corner and the little girl's body is completely enveloped by a large plastic dry cleaning bag she put on over her head. (You're thinking OMG, she could suffocate). Betty say's,
"Sally Draper, you come here, right now! You better hope my clothes aren't rumpled in a pile on the bottom of my closet or you are really going to get it!".
That was back before they stamped "This Bag is Not a Toy" all over everything.
Anyway, my point is, take good care of yourself, get plenty of rest, and don't worry too much about the things on the Do Not list. Certainly take precautions, but don't worry if you did something on the Don't list that you didn't know you shouldn't do.
If that makes any sense.
Best of wishes and I look forward to hearing more about what the fish tank thing is all about.