I think it is ok. I wonder whether the concentration of your sample is high or not.If it is high enough,you can dilute it so it won't be any problems for your sequencing.If not,you can use the ethanol to purify it.Anyway,I suggest you can have a test to RNA library first.

I have noticed that you isolated RNAs from single zebrafish embryo, so it is a very important information that how many cells you used in this step (sorry, I am not familiar with zebrafish embryo at the 8ss). For using few cells to isolate RNA, the 260/230 is always lower than that using large number of cells( You can get some more information in the attachment).

Laurence is right, salt contaminants, phenol and GITC, can influence the A260/A230 ratio, for they all have a absorbance at A230. Re-purify you RNA sample with an additional alcohol precipitation( adding NaAC; if the RNA concentration is low, you can also add LPA(linear poly-acrylamide) or other reagents that help precipitation of nuclear acids) may alleviate the problems. best wishes!

I agree with Laurence Stuart Dawkins-Hall

Dear Hannah, apart from the explanations and suggestions you received here, I would simply add few more points, which you can also look for this decreased A260/230s issue. Definitely, some other factors also impart in low 260/230 ratios quite away from the fact of salts overloading in your RNA samples and these are;

If you carry out the Blank measurement on nanodrop, which has dirty pedestal pin, or has not been taken care properly since long, you may observe low 260/230 values.

Less RNA yield (poor extraction efficiency) also leads to low 260/230, but here if in your samples the RNA quantity is appreciable then it is fine to ignore this point.

Often, RNA is dissolved (final elution) or stored in certain buffers suitable for it, and during measurement we blank the nanodrop by simple nuclease-free water rather using that buffer to blank the instrument and thus this decreases the A260/230 ratios.

If the cDNA synthesized from your RNA samples (of low 260/230s) shows good and stable ct values for a certain housekeeping gene, so it means GITC or any other salt is not your issue and there is no enzyme inhibition at any step. So, I suggest that in such case RNA with good RIN and good A260/280 can go for RNA-Seq despite having low 260/230s. It logically should not make much difference.

And, since your A260/280 ratios are very fine, I would certainly recommend to look into these suggestions I just described.

Sincerely....