Fish was thrust into the action for his first minutes of the season against the Hornets after Dylan Lawlor went down clutching at his hamstring.
Wales international Lawlor had only just returned from his own injury, and was making his second start of the campaign before being forced off after 29 minutes.
Fish has been recovering from hernia surgery, and feels he has more to go before declaring himself fully fit, although he is in a much better place than he was.
“It’s never nice to get injured, especially as we came back for pre-season. In effect, I’ve not really had a pre-season. I’m almost playing catch-up at the minute,” he said.
“I feel like I’ve got a long way to go, but it was nice to get out there on Tuesday night and get some minutes into my legs.
“My injury, you can’t help that. It is what it is. I got over it, and I feel like I’m in a good place now, and I’m ready to help the team.”
Cardiff established a 5-0 lead with five minutes of Tuesday’s game remaining – only to concede a late Watford consolation shortly after.
“I was disappointed,” admitted Fish.
“At that stage in the game, of course, we could have done better. We were all hoping for the clean sheet, but it was nice to get three points.”
Cardiff are yet to keep a clean sheet since winning promotion back to the Championship and face a tough challenge when they head to second-place Middlesbrough on Saturday, October 17 (12:30 BST).
Like Cardiff, Kim Hellberg’s side rank among the best performers for shots on goal and touches in the opposition box.
After a trip to Teesside, the Bluebirds face further tests against Birmingham and relegated trio Wolves, West Ham and Burnley.
Fish is not looking too far ahead. Instead, he wants his side to lay down a marker by becoming the first away side to win at the Riverside this season.
“The games we have got coming up are tough. Every game of football that you play in this league is tough. We will just take it game by game,” he said.
“[Watford] was a good start, and hopefully we can pick up another win in Middlesbrough on Saturday.”