Here you will find the Spanish fishing manuals published by each region’s government, so that you can check out the different kinds of fish you will find there, what you’re not allowed to fish, minimum sizes, etc. They’re all in Spanish.
Gran Canaria minimum fish sizes: at the bottom of this page, you will find download links for the big images
Canary Islands minimum fish size tables: Below you will find links for minimum sizes, regulated by the Canary Islands government, the Spanish government, and the European Union.
Government of Baleares Fishing Manual: Although it is from 2017, not much has changed. Click here to have a look at it
Euskadi (Basque Country)
This manual is in Spanish and their local language Euskera. Click here to read it
Minimum Size Limits for Spain
This website has nice photos with minimum fish sizes. If you’re doing catch and release, you have nothing to worry. It’s only if you want to eat the fish (or use as live bait, where it is allowed), you must pay attention to the fish lengths. Each fish has a table, with the different fishing regions. Click here to check it out