From crochet.about.com - Tropical Fish With Valentine Heart
An original design by Sandi Marshall
The color key above shows numbers corresponding to three brands of embroidery floss. When doing a cross-stitch of the chart on a thread crocheted background, embroidery floss will be used. When making this design with yarn (such as for a pillow or afghan square), use yarn in your choice of similar colors for the cross stitch portion.
You can work the chart either of two ways:
Crochet The Colors In As You Go
Cross-stitch the Design on a Crocheted Background
Read the chart as 1 square on the chart = 1 single crochet stitch.
The chart is 50 stitches across and 50 rows high. To make a crocheted background the same size as the chart: Make a starting chain of 51 chains (for 50 single crochet). If crocheting a background in afghan stitch, starting chain is 50 chains (there is no turning chain in afghan stitch). Crochet 50 rows.
Changing Colors How-To (Photos) - http://crochet.about.com/library/weekly/aa041203.htm
How To Cross Stitch on Single Crochet - http://crochet.about.com/library/weekly/aa111702.htm
The design and charts
copyright 
2005 by Sandi Marshall,
licensed to About.com, Inc. Free
for your own personal use only. Finished items that include this design may not be sold (which would be a commercial use, not a personal use of this design). If others would like to have the
pattern, do not give them reproduced copies or scans, per copyright law, but instead,
please give them the URL of this page, so that they may
come here for themselves. Thank you.
URL of the main page for this design is
http://crochet.about.com/library/weekly/aa021305.htm
URL of this printing page is
http://crochet.about.com/library/n021305.htm
How long does copyright last? See US Government Copyright Office web site at http://www.loc.gov/copyright. Under "Publications" heading, click on "Information Circulars": Circular 15 (Renewal of Copyrights), Circular 15a (Duration of Copyrights) and Circular 15t (Extension of Copyright Terms) will be helpful.
Copyright and Patterns - Copyright Law Links:
http://crochet.about.com/od/copyright/
Copyright Myths Explained - www.templetons.com/brad/copymyths.html